In order to answer your question, I would have to look at what the deed that you have written about states. I presume it is a joint tenancy deed. If so, under the laws of all states, unless the deed is changed, the surviving owners continue to inherit in equal shares the ownership interests of those designated that passed.If such is the case, a buy out could result either voluntarily or by court order in a partition action. I suggest that you consult further with a real estate attorney about your matter.