Legal Question in Civil Litigation in Michigan

Your son moved "without notice"? Did you have a formal rental/lease agreement that required him to give "notice"? Probably not. Do not destroy his belongings, and do not throw them out into the street. Pack everything up, and send him a registered letter telling him to come to retrieve his personal belongings. If you don't have his current address, send it to your address and hope that he filed a mail forwarding order with the USPS.

Your obligation to him depends a lot on the specific facts of your situation, and his. A real estate attorney can help you to determine the next step by applying the law to the facts of your case.