I reckon she was afraid to report it, being in such close proximity. Even with evidence, reporting things can be difficult. She should've done something immediately. I fear her lack of action may be interpreted as guilt or condoning, as you say. The police are likely to want a good reason why she's done nothing, especially with evidence. It might be different if she had no evidence.

I would be terrified to live beside someone like that, and the first time they would do that, would be their last. But it's not so easy in reality. This person has made her life a living hell. With all the evidence, there is a high chance he will face prosecution, or as you say there is something wrong with him and he needs help.