Is it permissible for the heirs to dispose of their mother’s money—she being of unsound mind—by putting it into a mosque or building a mosque with it outside the Kingdom, knowing that sometimes she requests that, and other times she asks for it to be given as charity?

If the mother is mentally incapacitated, her property is interdicted and held by a guardian, and her dispositions over it are not valid due to her lack of legal capacity. The mother's ownership of the property remains as long as she is alive, and it is spent on her needs. It is not permissible to donate this money for building mosques or voluntary charities; rather, it remains hers until she recovers and it is returned to her, or she dies, at which point it transfers to her heirs, and they may then give charity on her behalf.