I'd ask what state but it doesn't make a difference here. Your Aunt needs an attorney and YESTERDAY. One that is shark like in nature. He's not legally married to your Aunt if she is still married to his first wife. If he obtained a marriage licence while married, in some neck of the woods, he can be charged with bigemy. Sell the possessions he left behind to get her the best lawyer money can buy.
Have your parents tell him to stop calling and if he doesn't file telephone harrassment charges with the local police against him.