She should make him something, that way she's still giving him a gift, but it wont be of any value to sell.
I know you say that he doesn't want to be a part of the family but maybe she could put together a photo album or something, pictures of him as a little boy then all along the way growing up. Even though he makes it clear he doesn't want to be involved in the family, if he received something like that and thought about good times as a child, its bound to make him smile.
All the best
x