Help!
We rescued a 4 week old kitten and immediately noticed his butt area was different than we’ve ever seen but it did not seem to cause him any pain. Initially he was doing well until he began having diarrhea and mucus/blood in his stool. We brought him to the vet and turns out he had a parasite called Coccidia. It was treated with a 10 day oral medication and we believed everything would be fine afterwards.
After the diarrhea subsided he began to be constipated to the point we had to bring him back to vet twice within a week for him to be sedated and his bowels to be manually released. They have no idea what would cause this.
We went to a specialized vet clinic and they said they could dilate the anus/rectum to help him pass his stool (may not help or may have to constantly have redone) or do a exploratory surgery to see if any tissue or something is in the intestines and such that stops him from passing by himself.
Our personal vet clinic says his anus is abnormal which may mean that he lacks the muscles to be able to push out his own stool.

We have researched online and found a couple pictures of kittens after they have had a prolapsed rectum and they look similar and symptoms seem about the same. He just does not have anything coming out of him.

Does anyone have any advice or personal experience that can help us? The specialized vet says if we can’t figure out what is causing this it would be best to euthanize him so he does not suffer. We do not want to do that. He is the sweetest and most playful kitten.