Is it permissible for a mother to write over a piece of land she owns to her son as compensation for her disposal of his private money, and would that absolve her from the punishment for devouring the orphan's wealth?

If what the state grants to an employee after his death is deducted from his salary, then it is an inheritance to be distributed according to Islamic law. But if it is a donation from the state, then it is not an inheritance and should be spent as the state stipulated. If the granting entity stipulated that the pension is specifically for the son, then the mother is not permitted to take from it except for her needs. However, if it was stipulated for the mother to spend on her needs and her son’s needs without specification, then there is no harm in what she took. What the mother took in excess of her needs from her son's money is a debt upon her, and she can write over the land to her son as compensation for that debt.