Young male cat

Question
I have three cats 15,6, and 3. I found the 3 year old as a stray two years ago in April and took him in to my home. The other cats were fine with him being in the house. He by no means is a normal cat. He runs around the house letting out a cry once in a while, destroying the furniture and everything else in his way. He is kind of like a puppy. When he is not acting like that he is so loveable. Sits on your lap, gives kisses, sleeps with you in bed and just a real lap cat. It's almost like he is two different cats in one. Lately he started peeing and pooping around the house so we put a fourth cat box in a another location in the house and he has been fine. Now he also sits at the top of the cellar stairs and does not let the other two down to use the boxes or let them come up if they are down, and he has been picking on the 15 year old cat. The vet won't offer any advice or medications. My husband is really starting to get upset with the bad behavior and wants to put him out. I don't have the heart to put him out or bring him to the shelter. That is no life for him. But I know something needs to be done because we have a baby in the house now, (he seams fine around her kisses her and she pulls his tail and he just takes it) but I don't want to risk anything happening to her. Please any advice you can offer would be great.

Answer
Hi Rebecca,  I am so sorry about your situation.  I mainly deal with health issues in felines.
This sounds like a cat that needs to have his own space and be an only cat.
There are many cats that don't do well with other cats.
How about you try to re-home him to a family with no other cats?

Sorry, that is my only suggestion for you.
Blessings!

Marie Peppers LPN MA