Question about Alfredo and his mom

I loved this movie. But I was confused about the relationship between Alfredo and his mother. She seems to resent him for something, and they fight about it. One time she tells him "you are all monsters" or something like that, but she clearly can't be referring to cannibalism since she is a part of that as well (and without any guilt).

Second time is when they fight after she slaps him when he said he will lead the family, and tells him he has always been like that, is basically referring to something that is wrong with him.

Is it that he is gay? But I wasn't sure if that fit the intensity of the scene and the resentment that seems to last for so long, also she never really directly made a fuss out of that the way she clearly did about the whore thing. Is it just that he is incapable of leading - but why then put him down at his most confident moment?

So how do others interpret the problems in their relationship?