BlackThorny: I kinda wish to play the devil's advocate here - what if he did send the gift to his son, assumed he'll be thrilled, then actually got a mark of disapproval from his son: "What is this Gog $^t you gave me, I only want a pile of Steaming bla bla".
That would actually make sense in that case to trade the gift for something his son could actually use (aka gems are like a Steam gift card).
Not knowing the situation, he still made a mistake.
If the ungrateful little shit isn't happy, boo hoo, he needs to teach that entitled son of his that the world doesn't revolve around him, or his wishes. It's never too late to teach appreciation for a noble intent (the thought behind the gift), and, in so doing, he might just have given his son a greater gift, the gift of understanding and maturing a bit.
If not, let him stew in the reality of contrasting nothing, with something, and get him socks next year :-)