Who is Bubeh, How does Mameh respond to Bubeh's death?

Bubeh is Ruth's grandmother on her mother's side, Bubeh, a diabetic, housed Ruth when she arrived in New York and worked in her aunt's leather factory. Bubeh passed away during Ruth's trip home to care for her ailing mother. Ruth reads a letter about Bubeh's death aloud to Mameh. Mameh never said a word at the time; later, though, Ruth heard her mother weeping: a sound that she would never forget.

Thanks a lot! Aslan.