What should I do?

So I got moses with 2 other kittens who were brothers. I seperated moses from his sister, the vet was happy with this because when mo tried to play or eat his mother and sister used to pin him down and not let him. Now he just isn't that friendly to people, while the two brothers are the sweetest things ever (I feel like this may stem from the fact that my application for an amazing kitty got usurped two times so I had to adopt my non-no1 choice). I am trying to be happy with this guy, and I feel like I am already attached, but how long should I expect to wait before I see his true colors? Also how does it impact him being the outsider to these two brothers, and what is going to happen when they are seperated in a year?

Well, a settling in period is normal - and that can vary from cat to cat.

Have a look at the introduction threads in the behaviour forum, which should help you integrate them.

Why are they being seperated in a year? It wasn't clear from your post.

Also, how old are they, are they neutered?

They are neutered, and they are being seperated because my roommate and his brother got the brothers, but i am probably moving out in about a year (they may come but i am not sure)

Ok, well being neutered will help with the settling down.

How old are they? Very young kittens? Several months old?

3.5 months

Well, some cats, like some people, are more aloof than others. Some of them are more outgoing than others. Some are one person cats, and they have little interest in anyone who isn't 'their' person.

The core part of his personality will have been determined by now, but it may take some time for you to discover it - he needs to settle in and some cats are just 'deeper' and less confessional than others.

Give him a chance to settle in. Play with him, read to him, groom, talk to him, sing to him - give him a chance to come to you - sit quietly reading aloud, just the two of you. When you bond a bit more you'll see to what extent he is affectionate, and how he likes to show it.

For example: one of my cats is quite aloof, and takes a long time to warm up to people. I thought he just wasn't a very friendly cat, but he is actually incredibly affectionate. He isn't much a lap cat, but he loves to cuddle while I'm sleeping, even giving up sunny afternoons outside if I'm having a nap in bed. The thing is, unlike a cat who will follow you for petting or who is more outgoing, you have to get to know him before you see the sweetness and the love.

In the morning he is generally more friendly, I usually wake up with him curled up next to my head purring... ashame hes not like this all the time Hes my sweetie though