Welcome to YT! He is a big one, I don't know if they can get that big, but mine is 12 lbs. You should def. take him in, he needs MAJOR TLC. Potty training is going to be hard whether its a puppy or not, he might be able to learn quicker, just depends. Thats horrible about his burn, that makes me want to cry
!!! Good luck!!! Please post pics of this little man.