Neglected Dog, What Do I Do For Old Maxx?

I used to have a beagle named Maxx. He is an ancient beagle and when I moved I had to leave old Maxxo behind with a couple who have several dogs. I recently saw him and he is in BAD shape he is blind and in pain and dirty and just a mess all around. He has no teeth but the people who took him don't bother buying him soft food. I Love this dog to death he is old but I can't have my daughter around dogs, (severe allergies). I don't want to see him euthanized and I know he can be happy and taken care of but I don't know who to contact. They also have several dogs that they just cant take care of and a horse living in mud with practically no shelter. I can't see these animals put to death, which is what the local "shelter" does after 14 days. What do I do??