What advice can you give on a situation involving a friend's probably sociopathic, possibly schizophrenic, scary-in-general ex boyfriend?

I posted this question a while back regarding this guy. The basic situation is that my best friend’s boyfriend went batshit after she broke up with him and made a death threat. Again, I’m going to call the best friend A, the boyfriend L, and their mutual friend S.

After that, L got a visit from the police telling him that he is to have no contact with A, and he has obeyed. Neither A nor S had heard from him in months, so we were all starting to relax about the whole thing. But, just the other day, S told me that L had sent her another crazy text message. He is having what I can only assume are delusions of grandeur. He claims to have written code that was capable of shutting down electrical power plants, he says he used it on a plant in Iran and blacked out a hospital and got people killed. He claims he got paid 20 million dollars for developing a spam bot when he was 15 years old, and that he used the money to bribe A’s college into accepting her and to fund her scholarship. He rambled on about how much he misses S and especially A. I already knew he was mentally unstable but now I really think he is off the deep end.

S hasn’t shown these text messages to A yet. The first threat left A feeling very depressed for weeks… she has moved on from L now and I hate to bring him back in her life, but I think she needs to know about this. Should I tell her, or encourage S to tell her, or leave it alone?

With summer coming up, we’re all going to be in the same town together again. A doesn’t have an official restraining order but L is banned on her college campus, so she has been feeling safe. What should she do to keep safe over the summer?

Thanks all. This situation is just nuts.