Broken jaw - feeding suggestions

Very thin 4 point showed up at my house about 10 days ago. Looks like it may have been hit by a car. very swollen possible broken jaw. tongue hanging out several inches and drooling. was not walking steady and walked right up to me. Coat was very dingy and dark more on one side. Have been feeding him anything he could lick up - protein pellets, mashed watermelon, finely chopped spinach, alfalfa, apples. Today, he is still super skinny but jaw is much less swollen, gait is stronger. His tongue is still hanging out but has recessed some now. He is now starting to fight back the other deer and is now more cautious which I think is good. His coat is looking better. He is trying to groom himself. Still seems to only be able to eat things he can lick up so items are cut super small. I think I hear some crunching sound so maybe once he gets it in he can crunch some? My questions - why or what injury would cause the tongue still be out? There is still a tiny bit of swelling on the underside. What are some suggestions of how I can get more nutrition in him? He eats for a good while but seems to always need water to help. When he licks so much, the pellets get damp and he has more trouble licking it. I added oats and it helps some. Any suggestions would be helpful. Would like to give him a chance and hope if he gains some wait then can figure ways to feed himself.