BackToMe, Please let a judge decide what is the best thing to happen to this person. That is why we have a judicial system. What he did to you is WRONG and what happens to him as a result is not your responsibility. You can't help him, and you can't control him but he has broken the law by what you say, you need to protect yourself from him, and he needs to be taught that it is not allowed. When people act in ways that are bad for society, and harmful to others, society needs to tell them that they are wrong and to try to convince him not to behave that way anymore.
This is a very dangerous situation for you, your sister and your children. Take the appropriate steps to protect yourselves. I personally wouldn't let him near my children (if I had any).
Just as scary as anything else is that he seems to really believe he heard and maybe even saw us together. Opiates (and maybe benzos) wouldn’t do that would it?
YES, what he is taking (which is probably not limited to just one thing) will make them hallucinate and filled with paranoia, and do crazy things. My brother was doing mostly cocaine but some other stuff, whatever he could get. For years, he would become intermittently obsessed about the telephones and how all the phones in the house were tapped. He tore apart EVERY phone in the house! He thought there were magic eyes in the T.V., watching him and his girlfriend. He would become hysterical over the fact that he thought his girlfriend was running an internet porn site and that the government was tracking his every move. He would get crazy talking about how the devil was coming into the house through the ceiling light. He said there was an electrical current from demons that would come through the house.
These people are dangerous.
Please get help.