I have a handicapped boy and he receives a monthly salary from the government. My wife wants to deduct 60 from it to sponsor an orphan. Can she do that even though it will have no affect on him and most of the money is spent on him and on the family.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The money granted to the handicapped is considered his own property. So, it should not be spent in anything other than what is beneficial to him. Therefore, the guardian or anyone else has no right to spend the money freely, regardless of how he spends it, as a gift charity, etc. If one does so, he is subject to return it. However, if a father or a brother are needy and need this money to spend on them, or to spend on those who are under their responsibility, then they may take only what meets their needs.
Allah knows best.