All four bought the place? If so, and he is a one fourth owner, he only needs to now buy the remaining three fourths. He is purchasing the interests of the other three owners.
yes, that is the basis of my statement. Was there something misleading in my statement?
anteater:
while your question is appropriate, the fact the OP is asking about 1/4 interest, it would make me believe there are only 4 siblings so I would think that the first part of your question is not applicable.
To the second part: obviously (to you and me) that too is not applicable as the mother no longer owns any interest in the home and as such, there is nothing to inherit from mom (at least regarding the house)
and also to nlverrone:
there is nothing that says that each of the siblings must agree to accept the same payment for their share. While how it is typically done: market value is determined, divided by number of co-owners (if owning equal shares) and the buyer pays that amount to each of the selling owners; there is nothing requiring any of you to accept any particular amount for your share. You can donate it to brother or you can demand twice market value if you want. It is entirely up to you (unless a court action called partition, is involved. Then the whole thing changes)