Peter:

"My brother is 40 years old and for the last few years I have seen a dramatic change in his personality. Up until a few years ago he was a kind caring sensitive person and would not hurt a fly."

My thoughts: this might be a clue. I can think of two possibilities. One, that there is some organic cause. That should be looked into. Two, if he felt he had to be extra "nice" growing up, maybe now he is no longer able to support that approach to life, and his real needs are becoming evident.

In either case I think he should (!) get help as soon as possible. Psychotropic medications are, in my opinion, not sufficient help all by themselves. I hope you can find somebody to pay attention before it is too late. Try to find someone. I know how hard it can sometimes be. Keep at it. In my area there are public mental health facilities that charge only by how much one can pay. I know that there is often a waiting period, but maybe the prospect of coming help will be enough to forestall any tragedies.