Is a will (Wasiyyah) valid for a child under seven, an insane person, or someone afflicted with the wasting disease (Mubtasam)?

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A will executed by a child under the age of seven, an insane person, or someone afflicted with the wasting disease is invalid. This is the established position held by the majority of scholars, including Humayd ibn Abd al-Rahman, Malik, al-Awza'i, al-Shafi'i, the People of Opinion (Ashab al-Ra'y), and those who follow them. The rationale is that the words and actions of these individuals hold no legal weight. If their acts of worship, such as their Islam and prayer, which involve pure benefit and no harm, are invalid, then their disposition of wealth, which potentially harms their heir, must be invalid a fortiori. Furthermore, a will requires offer and acceptance, making it invalid from those incapable of contract, similar to a sale or a gift.