My sister has dumped her boyfriend who's also the father of her two children. The reason why she has dumped him is because he is obviously a psychopath and that is also the reason why i believe she and her children are currently in great danger. I am absolutely shure that this man is planning to hurt her or her children.

There seems to be no clear solution to this problem. Remaining a positive human being, while faced with these threats is a great challenge and i don't mean challenge as a positive thing here.