Kitten who just seems odd/off?

I had a kitten once that I think was def. He was the same as you describe yours around loud noises that would normally scare a cat. Mine would just lay there and you could run him over with vacuum if you didn't stop because he would not move. He acted funny compared to our other cats but we just accepted his uniqueness and we enjoyed him alot. We just had to be careful because he couldn't hear therefore he would not move if he didn't see something and would almost get stepped on and other things. I would talk to the vet though. My brother had a cat once that he had adopted. As a kitten his head was slammed in a car door and he was never the same. The old owners were gonna kill him so my brother took him in. He was super weird. He would be doing something and suddenly just freeze like he forgot what. He would be in mid step with foot in air and just stop. He would stay frozen for sometimes up to 30 minutes or more if you didn't go remind him that the was moving. He probably would have stayed longer but that is the longest we ever let him stand like that before we went and nudged him or something to remind him that he was moving to go somewhere. He was a super sweet loving cat just mentally not right from the head trauma he received. The vets said there was nothing to do but love him and accept him the way he was. They explained he was kinda like a mentally handicapped child and we just had to accomadate him the best we could. As far as eating I think he is just a picky eater. I have a perfectly normal cat in every way except he will only eat one kind of food. He won't even eat tuna. I give all my cats some every now and then for a treat and he turns his nose up. I have never before him seen a cat that didn't like tuna. But he just prefers that one kind of food and its not even a real good brand (Alley Cat) But thats all he will eat so I feed it to him. Any way good luck!