We return to the scene we left at the start of intermission, as Big Daddy makes his big entrance into Maggie and Brick's room. He is joined by the rest of the family and the Reverend, whom Big Daddy mocks for fishing around for donations. A general conversation is broken by Big Daddy cruelly mocking Big Mama, who takes it in stride and hides her hurt for later.
The children sing "Happy Birthday" to Big Daddy, who gets exasperated with Big Mama for showing too much emotion – she's just so happy about Big Daddy's clean bill of health. Maggie and Mae snip at each other, and through the general clutter of inane talk and griping, Big Daddy attempts to find out why Brick was jumping hurdles at three a.m. Big Mama tries to stop his questioning, and he turns on her.
The rest of the family quickly leaves the room to give the older couple some space as Big Mama rails at Big Daddy for talking so meanly when she knows he doesn't mean it. He makes a speech about how his wife had been angling to take over the plantation ever since he started getting sick, the plantation that he worked all his life to grow; now that he is no longer dying, he intends to return to his rightful place in charge of the estate.
Big Mama explodes with hurt and truth – "in all these years you never believed I loved you??" But Big Daddy bears this no mind, and says to himself as she leaves, "wouldn't it be funny if that was true?"
He calls for Brick, who hobbles in with his drink. Big Daddy points out that Maggie and Mae have much the same look about them – two very different brothers married the same sort of woman. Big Daddy has a mind in him to talk, but Brick isn't much interested. Big Daddy then dismisses all eavesdroppers; he is upset with Mae and Gooper for listening in on Maggie and Brick's fights at night and reporting back to Big Mama.
He asks his son why he drinks, and Brick has no answer. He says that he just keeps drinking for his click. Big Daddy reminisces about a trip to Europe, a really dreadful affair on which Big Mama bought everything she saw and Big Daddy was roundly disgusted by starving peasants in Spain and under-age prostitution in Morocco. He observes that men buy and buy and buy things with the vain hope that they can buy immortality. Brick just wants him to shut up.
Big Daddy continues to talk about how he'd been so afraid of dying, but now that the weight has been taken off his shoulders, he is going to live life for real – beginning with jump-starting his sex life. He slept with Big Mama till he was 60, but he never much liked it, and will now be in the market for a mistress.
Brick is still restless, waiting for his click to make him peaceful. This makes Big Daddy keenly aware of the fact that his son is an alcoholic. He pulls the crutch out from under Brick, and won't let him leave until he listens to him. Big Daddy talks more about his relief at being healthy, and ignores Brick's remarks that they only ever talk round and round in circles.
Big Mama interrupts them, and in the ensuing shouting, Brick tries to sneak over to the liquor. Big Daddy trips him, and won't help him up or give him a drink until he says why he drinks. "Disgust" is his answer, but he can't say disgust with what. Big Daddy presses him, and he adds "mendacity," a frustration with a world of lies and liars. What does he know of mendacity, Big Daddy asks. Big Daddy has filled his life with pretense, when the only things in the world he cares about are his plantation and Brick.
Brick adds that he is avoiding life, and this infuriates Big Daddy, with his recent brush with death. When he thought he was dying, he was torn over whether to leave his property to Gooper and Mae, whom he hates, or Brick, whom he loves but who is an alcoholic. Now that he isn't dying, he doesn't have to worry about it for fifteen or twenty more years, and is making up no will.
He goes back to pressing Brick about his reason for drinking, finally zeroing in on the truth that Brick started drinking when Skipper died. Brick's detachment is finally broken by this truth, and violently defends accusations of "impropriety" in his relationship with Skipper as Big Daddy backs away meekly. The old man says he understands all sorts of relationships, having been a hobo in his day before coming to work for the old gay couple that previously owned the plantation, and in whose bedroom they stand. When one of the old men died, the other stopped eating till he died too – and when Skipper died, Brick began drinking.
Brick still angrily flails at the unspoken accusation of sodomy – the idea has clearly been well-ingrained in his psyche as repulsive. Their friendship was white and pure, and the fact that anyone names it dirty shows how little they understand the rare and beautiful thing that is a true friendship.
He breaks into an angry monologue about how he and Skipper tried to stay in football after Ole Miss, but Brick got injured and Skipper got drunk. Maggie put the idea into Skipper's head that he and Brick's relationship was less than proper, and Skipper slept with her to prove her wrong.
Big Daddy knows this story is missing something, and presses until Brick admits that he left out a phone call in which a drunken Skipper made a confession and Brick hung up – this was the last time they ever spoke to each other. Big Daddy declares that this is the mendacity that disgusts Brick, the truth that he wouldn't face with Skipper. Brick furiously asks just who can't face truth, and lets slip that Big Daddy is not after all in perfect health.
Brick tries to take back the beginning of the admission, but Big Daddy holds him to it. Brick doesn't say more, but Big Daddy can read between the lines, and knows now that he has cancer. Brick apologizes for speaking the truth, but that's what Big Daddy just did to him. Big Daddy rushes out, shouting angrily, as Brick remains motionless and the curtain falls.
In the second act, Williams takes the revelations of the first and follows them to their inevitable conclusions. Coming out of the first intermission, we know that Big Daddy's is going to find out that he has cancer, and we know that Brick is going to be forced to acknowledge the truth about Skipper – but we're not yet sure how this will play out. The long second act serves to pull these two revelations together in an emotional, drawn-out confrontation.
After the long exposition of the first act, there is surprisingly little new information in the second. The only new information is that Brick hung up on Skipper when he tried to make a confession – and we probably guessed as much already from how he'd reacted to Maggie's previous accusations. Therefore, a performance of the play must rely entirely on the audience forming an emotional connection with the characters, such that we are hooked solely by the prospect of seeing how they react to these revelations, rather than the content of the revelations themselves.
This is no small task that Williams puts before his actors. The first act rested squarely on Maggie's shoulders – now she has been given an act in the wings while Big Daddy holds court for this entire long act. Both acts show us an extended portrait of a person who loves Brick more than he is capable of loving back, and their attempts to break through his glaze of alcohol and depression. Big Daddy is the more successful of the two, in that he succeeds in getting a rise out of Brick, but the man remains closed off and hurtful. We now have a better idea of what happened to him, but we still don't really know why.
For this to be effective, the audience must feel, as Maggie and Big Daddy do, that Brick is someone worth knowing. Williams slides into didacticism in his stage directions towards the end of this act; right before Brick's surface begins to crack, Williams warns that he wants his hero to remain inscrutable, "just as a great deal of mystery is always left in the revelation of character in life." This challenges the actor to be simultaneously opaque and enthralling, while giving a sense of revelation and breakthrough to a scene that retreads familiar material.
A parallel is set up between the marriages of Brick and Maggie and of Big Daddy and Big Mama. Both women are in love with husbands who can't stand them, and who lost interest in sex long before they did. Depending on how the actor plays Big Daddy's lines about his time as a hobo, it can even be implied that he may also not be entirely heterosexual.
Big Daddy is a peculiar character, the sort that Williams specializes in – the plain-talking, down-to-earth redneck who nevertheless serves as the author's mouthpiece for the truths and themes of the play. Like Stanley Kowalski before him, Big Daddy is crude and angry and uneducated, but given to him are lines like "[a man] buys and buys and buys [in the] hope that one of his purchases will be life everlasting" and "why is it so damn hard for people to talk?" – the key lines that encapsulate Williams' intentions in this scene.
For all his gruffness, Big Daddy is the voice of the playwright – he is Williams' tool for announcing his themes and prodding his characters into stating painful truths. He is, in sum, a plot device – but a plot device who was well set up by the first act so that, in a strong performance, the audience will never realize that the character is merely serving a narrative role.