if he buys the house using his money and immediately puts you and your spouse on the title he at that time has made a gift to you of 1/3 of the house or 133,333 for you and your spouse for which a gift tax return would be required, then in subsequent years he could making additional gifts to your of parts of his interest. to avoid any initial gift he would have to keep your names off the title. now the potentially expensive downside. see a real estate lawyer because of state/local laws regarding transfers of interest. it is possible that every year he made the gift, to make it official, it would need to be recorded. this could result in the imposition of transfer taxes each year. Unless his estate is over like $12million there would be no federal estate taxes when he passed. so an immediate gift of $400,000 would cost nothing. Florida laws could be different so the absolute need to consult a real estate lawyer.
