How much of the tongue (if any) is left? It is likely quite painful for him and may be uncomfortable too. Do you see him flexing his gular pouch or acting like the tongue/hyoid spike (the bone that the tongue rests on) isn't sitting comfortably in his throat? The tongue is like a tube that slips/folds over the hyoid bone a little like the way you slide a sleeve up your arm. If the end is missing, then the tube is open on the end and may retract uncomfortably onto the bone. When the tongue is amputated, it is sutured on the end and just enough to cover the bone without stretching it is left unamputated.
You said..."I am giving him antibiotics for two weeks and he appears to drink misted water" good on both counts! Since he is drinking, when his mouth is open try sticking a waxworm or a silkworm in between his teeth...I'm suggesting these because they are softer and easier to chew so it may cause the chameleon less pain to eat them. I have had several chameleons that got their tongues tangled and they had to be amputated...and they can't figure out at first that they can no longer shoot their tongues at a bug but have to walk up to it and eat it.
You said..."I need any suggestions on teaching him to take crickets by hand"...I always tried the method above first. If the chameleon took them this way, then I would try moving the insect away from him a little bit. It usually worked. If they get hungry enough they usually figure out that they have to walk up to the cricket.
If the tongue feels uncomfortable to the chameleon the chances are less likely that it will learn to eat on its own.
Hope you can get the chameleon to eat on its own! They can live a normal life span if they do learn it.