Lifeless Bearded dragon

Question
I have had my dragon for 4 years. He is approx. 7 yrs old. He use to be in a cage with another dragon his size(Up unil about 6 mo ago)until the other dragon bit him pretty bad. We had applied antibiotics to his wounds, but he still lost his tail. We always used a night/day lamp, but JUST learned that it should have been UV rays!! His diet consists of red lettuce with calcium & crickets with Calcium. A few weeks ago, he started turning a deeper brown, but I thought it was just shedding. He has lizard sand on the bottom, a heat rock, and a fake log so he can get closer to the lamp. About 2 weeks ago, he really became lifeless. He now hardly moves, and his back legs are twitching. He hasnt passed a bowel movement in a week. He eats crickets if we put them right in front of him, but wont eat lettuce of drink. We have been giving him a warm bath, and mineral oil for the last day. I am trying to make him drink with a dropper. His eyes are hardly open. The person I bought him( a reputable reptile seller) says it is old age. I have read he could be impacted, but she says no. We live in the middle of no where, and our local vets have no clue. The closest vet is 2 hours away. Do you have any suggestions? If he is suffering, is there a way to humanley put him down? I dont want him to suffer. Thank you for your time!

Answer
Hello Lincoln, the UV lighting is very important and its too bad you didn't have that before hand. I am very sorry for all of this but I can definately point out some mistakes.
1) they need the uv lighting which you say you just found out about
2) Sand is a big no-no even if it is made for reptiles it can and has been deadly before. It should never be used for any reptile.
3) Heat rocks are also very bad, they get to extreme temperatures and 90% of the time burn the belly of your animal. They should be avoided.

Fixing those things should help.
It does seem like there isn't much more you can do for him. It could just be his age, it is very likely that it is just his time. If there is no way you can get him to a vet then you do need to put him down. Now I do not usually recommend ways to put down your animal but I hate to see animals suffer. The vet is the BEST way to euthanize an animal. Any vet should be able to do this. Now I know somebody who took a tupperware bowl and lid poked holes in the lid and placed the lizard in their and then placed it in the freezer. Because they are cold blooded they need heat to survive. I heard it is quick and easy, but again I do not beleive it is the best. But I don't like to see animals suffer. You want holes so that he doesn't suffocate first because that is suffering.
I do not know anything you can do besides taking him to a vet.
check out this site though and see if there is anything you can find first.
Good luck
http://www.beautifuldragons.com
Sorry and I hope he gets better.