I think the bullying claims were exaggerated a tad, but I believe there's no smoke without fire and they did admit things got a little 'tense' in rehearsals.
I suspect his age is catching up with him making him extremely tired, and he probably lost his temper with Amy while rehearsing after a long day. She was probably tired/stressed too, and broke down. That said, he does come across as a little arrogant.