No to the first question, unless he can argue you've contributed absolutely nothing to its purchase, cost to maintain, bill paying and upkeep, and that you being added to the title was gratuitious. Unlikely. If you took title as tenants in common, yes he can leave his share to his son in a will. If you took title as joint tenants with right of survivorship, if he dies, you will inherit and that will override anything he has put into a will.
To questioners from West Virginia & New York: Although I am licensed to practice in your state, I practice on a day-to-day basis in Massachusetts. I answer questions in your state in areas of the law in which I practice, and in which I feel comfortable trying to offer you assistance based on my knowledge of specific statutes in your state and/or general principles applicable in all states. It is always best, however, to work with attorneys and court personnel in your own area to deal with specific problems and factual situations.
Laws vary from state to state and you should always consult with a local attorney.
You do not state how the property is titled.
If you are joint tenants, and something were to happen to your boyfriend, you would become the sole owner.
If you are tenants in common, then you each own 50% (unless a different share is noted on the deed). Your boyfriend would be free to transfer his interest to someone else.
Your boyfriend cannot extinguish your ownership interest in the property.
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