can you sue a murderer?

In civil court its called wrongful death. You need to talk specifics with a lawyer.

Your son will be 28 by then, and old enough to seek legal advice on this for himself.

It is normal for jurisdictions to have some kind of law that prevents a murderer from making money directly from his crime. So if someone murdered you for the inheritance, they would automatically be disinherited.

But ex-prisoners are not barred from having money or from inheriting money, so long as it is not inherited from their victim.

By the time this man is freed, if he is freed, he will have served at least 37 years. I would rather move on than spend 37 years stewing over this, awful as it is.

You could file a civil suit, but I don't know about this late date. Speak with an attorney.

I don't think so. He has already been punished by the law so yea.