What to do with my angry misbehaving cat? Is there something wrong with him?

I have a 3 y/o ragdoll, he is very moody!!! And my mother is threatening to find him a new home if he doesn't stop getting into trouble. I swear he has a mental issue, if I don't let him in my room (I can't, I have allergies and there is too many things he will get into) he goes into the hallway and pees in front of my door :l I put him in the the litter box but it doesn't help, he still pees! We thought he may have something wrong with him, so we called the vet.....well they said just give him antibiotics. It didn't help at all. He knows were the litter box is, he does use it but it's like he hold grudges on me XD cuz it only happens when I don't let him come in my room and he only pees in front of my door (also in the bathroom which is right next to my room). He also doesn't like to get pet, he throws a fit if anyone try's to pet him/hold him. He'll only let me feed him and he won't eat nothing but expensive caned food, I tried feeding him a cheaper brand, tried mixing in hard cat food also, he just won't eat it. He has his 'off' moments were he will just be sitting on the counter then like fall out of nowhere, we just found out he was inbred (which is very upsetting) he had a older brother named Tiggy, we had him for 3 years also but he got sick suddenly then died 2 days later :(( before we even had time to realize he was sick. Tiggy didn't act sick at all, he ate normal, didn't throw up, didn't act out of the norm. He gained 5 pounds in 2-3 days then he just layed around the house until the last day. I'm worried that my cat will die too but dad says this misbehaving is just his attitude and he refuses to take him to the vet unless he acts sick :(( He also likes to terrorize my moms chihuahua and he attacks nearly every dog/cat that comes near. (all cats terrorize pups but it gets troublesum) I can't even start explain his attitude problem properly, it's just horrible. He's very happy one moment then very angry the next, it's like he has bi-polar! Or multiple personality disorder!!