The Question and Answer section for The Perks of Being a Wallflower is a great resource to ask questions, find answers, and discuss the novel.
Charlie was awake and bored. He calle the number because it was available, and because he knew someone would be on the other line.
I'm not finding any information that correlates with your question. I don't even see a diary entry for 1/4 or January 4th. Please check your question and correct if necessary.
Brad and Patrick are involved in a homoerotic relationship. Brad wants to keep it a secret because he does not want people to find out he is gay.