Mom was dead two months before stepdad. He refused us anything and even strangled me on the day she died. Sad. Owed him money. Now he killed himself and his daughters who never even hardly visited think it's all theirs. What are our rights?

Depends on whether your mom had a will. If not, he probably inherited a portion of her estate. Check the intestacy laws for your state.

As noted did mom leave a will? The inheritance laws have many variables see here Intestate Succession in Minnesota | Nolo.com. But his children are correct, you have no rights to his estate. On the other hand, if there was no will you may have a right to a portion of mom's estate.