What is the ruling of the Sharia regarding a deceased father's will bequeathing three-quarters of his property to two of his sons, knowing that he was ill and suffering from memory loss before his death, and that there is no bequest to an heir, and that one of the two sons to whom the bequest was made claims that he promised his father to fulfill the will?

1. A bequest to a non-heir, for one-third or less of the estate, is permissible by consensus (ijma') and does not require approval. However, a bequest to an heir is permissible only if the other heirs approve it; otherwise, it is not enforceable.

2. If one of the heirs carries out the bequest without the knowledge of the others, the execution is invalid, and the money must be returned and divided among the heirs.