Are the father, paternal uncle, and paternal aunt entitled to claim inheritance in a house that the grandfather relinquished to the questioner on condition that it be returned by the state, after the sons agreed to that, and must one relinquish it to them?

If the donee (grandson) repossesses the house and takes possession of it during the lifetime of the donor (grandfather), then the gift is valid and enforceable, and no one has the right to dispute it. However, if the donor dies before the house is taken possession of, then the gift is void, and the heirs have the right to either uphold or revoke it, and the donee must surrender the house to them.