Dying tokay

Question
Ive had my tokay for years now. I pay very close attentions to his actions. I realized about a week ago that there had been an unusual amount of crickets left in his cage, and that when I did feed him, he didnt go after them like he used to. Hes lost weight, doesnt move, rarely does he move, and he doesnt fight, bark or even try to move when I pick him up. Ive been feeding him food concentrate with caloric supplement, thats a enduces and appetite and also gives him an energy boost for a couple of days now, and misting him with vitamin spray for reptiles that gets absorbed through his skin. His cage is at the proper humidity, Ive been keeping his night lamp on during the day to make sure he is plenty warm enough. Ive ruled out mites, even though I was hoping that may have been the issue because it would have been easily solved. I have changed the cage since he became this way, I used a mulch, now I use paper towels so I can moniter whether he is going to the bathroom or now. Which he has. Any and all advice would be greatly appreciated.

Answer
 How many years?  8 to ten years is normal in the wild, with some surviving into their teens in captivity.  If he's near ten, then he really should get more regular geriatric check ups at the vet.  If he is pooping, then he's eating something, he may be just slowing down.  Have him checked as soon as possible to rule out anything medical, and then follow the vet's advice in regards to any changes in diet.  You may want to consider trying some silkworms as a food higher in digestible calcium and have an enzyme very beneficial to the aging lizard.