Is it permissible for a mother to give money to one of her sons to the exclusion of others, using the money of the elderly father who does not manage his finances well, knowing that the son is currently unemployed, and that the father did not give his children money when he became incapacitated from work?

If a father reaches an old age where his mind is affected and weakened to the extent that he cannot manage his wealth, he is placed under interdiction (hajr) and his actions are not accepted. His wife is not entitled to dispose of his wealth or give any of it to their children. Rather, the matter is referred to a judge to place him under interdiction and appoint a guardian to manage his affairs.