What is the ruling on relinquishing a house to a seven-year-old son, and does the omission of mentioning possession (al-hiyazah) and disposition (at-tasharruf) in the relinquishment document affect its validity Islamically, especially since the text states, "The relinquisher has authorized the relinquishing party to accept and possess it"?

The one who takes possession on behalf of a young child is his father or whoever acts in his stead. As for the young child's own act of possession, it holds no weight. So, if a father gifted a property to his young child and took possession of it on his behalf, and bore witness to the gift, then the possession is sufficient and the gift is complete.

It is stated in Sharh Tuhfat al-Hukkam by Mayyara: "Ibn Wahb narrated that Abu Bakr, Uthman, Ibn Umar, and Ibn Abbas, may Allah be pleased with them, said: 'No charity or gift is permissible except by taking possession, except for a young child of the giver, for his father takes possession on his behalf, and this is for properties other than a dwelling house.'"

As for a dwelling house, the father's possession and bearing witness are not sufficient for the validity of gifting it to the child. Rather, the father must vacate it and clear it of his furniture. If he does not clear it and remains living in it or in most of it until he dies, the gift is invalidated and the house becomes part of the inheritance.