BonBon
I once let a significant other move in with me because his living situation wasn't working for him. This was NOT the right reason for the two of us to start living together. It was not a choice that we both consciously made and wanted. It was just an alleviation to his discomfort at where he was living. Needless to say, it didn't work out.
What he is telling you sounds like blackmail to me. "Let me move in with you, or I am going back to Michigan". There are definately some red flags here, pay attention to them.
Hugs to you.
Peace,
Gabe