I dont have an issue with him holding the feet to deter.
I do have an issue with requesting the dog come up and then doing it. So what happens when he wants the dog to actually jump up?
Personally, I just teach my dogs not to jump in the first place. And the way I do it is by walking with my hands out in front of me, and saying "No" the minute they look like they are about to jump. The only one who hasnt learnt it is Pippi (she only reaches your knee so is allowed to jump up, until you tell her to stop of ocurse, and shes not allowed to do it to other people, and she doesnt but Im not sure how I got that message across LOL). They have all learnt (except Pippi) they do not jump up unless invited, and once they jump up they must get down when told....easily taught by pushing them off when youve had enough LOL.