What is the ruling on a house for which the husband began the procedures of gifting it to his wife, but the transaction was not completed, and the wife died first, then the husband, knowing that the heirs completed the registration of the house in the name of the deceased father and then in their names as legal heirs? Is there any sin in their action, and must they give a share of the inheritance to the heirs of the wife's mother?

If a man grants something to his wife without his children, there is no harm in it, unless the intention is to harm the heirs, in which case this grant is considered forbidden and void. A grant is not binding merely by initiating it; rather, it takes effect and its consequences are established upon the recipient taking possession, whether through official registration or by enabling the wife to dispose of the granted item before the grantor's death. If the grant is valid and the wife has taken possession of it, the house becomes her property and that of her heirs after her death. However, if the husband initiated the grant but then revoked it before the wife could dispose of it, or if his intention was merely to write it to her so it would be hers only after his death, then the grant is not complete, and the house reverts to the husband's heirs. If the situation is unclear, the default is that ownership remains with its original owner.