Ask a landlord-tenant lawyer and get answers ASAP
Good afternoon,I'm Doug, and I'm very sorry to hear of your situation. My goal is to provide you with excellent service today.
Your 18 year old son is no longer legally your responsibility and you have the right to demand that they leave and find a place of their own to live.
You will need to give your son a written 3 Day Notice to Vacate explaining that he has no lease and no legal right to remain there in your home. After 3 days if he has not left, then on the 4th day or after that, you will want to file formal eviction proceedings in court and get a court order for the eviction.
You may reply back to me using the Reply link and I will be happy to continue to assist you until I am able to address your concerns, to your satisfaction.Please be so kind as to rate my service to you. That is the only way I am credited for assisting you.I wish you and yours the best in 2016,Doug