Rose, Gabby's friend, said that he had episodes. I'll take her word for it. For now.
He had "episodes" of insomnia, hallucinations and hearing voices, according to Rose. Now, that being said, most people who think they're "hearing voices" aren't, at least not in the psychiatric sense. And sleep deprivation can cause hallucinations. But what would cause that degree of insomnia?
It sounds to me as if BL had a lot of excuses for his behavior, which apparently Gabby believed and told her friend about. We haven't discussed this, but one reason a young woman stays with a difficult, tantrum-prone, easily frustrated young man is because she feels he has some kind of "issue" where he "needs help," and she wants to help. I think BL was highly dependent on Gabby in so many ways...