You do not have a life estate. You are a jont tenant and he has as much right to live there as you do. If he dies first, you get the entire property. If you die it all goes to him unless you transfer your joint tenancy to someone else. You may want to see about putting your half into a trust giving yourself a life estate. You will need the assistance of an attorney.
To answer your question, he has the right to move in with you.
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