Wow, that is a tough one. I don't know what it is like to deal with the tongue issue. Mine was the roof of my mouth. I didn't have one which made swallowing anything a little more difficult. They actually rebuilt mine so now things are easier to swallow but I have no desire to. And most things don't even smell good which doesn't help the desire part. I am not able to even try solid foods as I have to upper teeth and some things are not appetizing pureed. ;-) I have only tried a hand full of things in about two years as well. I have bad dry mouth and when I do try things I have to drink a lot of water to help get it all down. I think to some degree it is just going to take a while and as long as he is trying and drinking the shakes, that's pretty good. He has not given up. Keep your head up and this to shall pass.