A deputy has the right to manage the money of a disabled person and spend it on their behalf, as long as what they are spending the money on is for the benefit of the disabled person. However, they do not have the right to make gifts of the disabled person’s money, other than small gifts for birthdays and Christmas etc.
So for example a deputy could not decide to give away £15,000 of the money belonging to a grandparent who has Alzheimer's to their grandchild, to help pay for a university education.