personally, i think it would be better to put him down if he's suffering
i've had to put down both my pets. my cat was sneezing blood for months and we couldn't find out what was wrong with her and she wouldn't eat anymore. my dog was unable to get up because his hips were forgeted and he pretty much had to drag himself around. they were both 18+ so they lived pretty long lives
if he can make it through, let him live. if he can't, maybe it's better to put him down instead of letting him suffer until he dies.