Maybe I should tell you. A lot of NTs are under the impression that we are not aware of the world around us. It appears this way because we do not react to it the same. This is actually false. I always know what is going on but the things around me look as if they are not controlled so I have no idea how to respond to them. Let me explain a few things to you from my point of view.

Sensory: Colors are vivid. Pretty much everything is enhanced, and when I see certain things they look so odd to me that I just cannot look at them. If I have to continue looking at them I will not like it because it's like having something you don't want to see right up close and you can't get away from it. All sounds are loud, and some make my ears hurt. A lot actually, like sirens. The sounds also make my heart beat fast. This is not pleasant. Then. There are wonderful things. Like water. My skin is made to feel things at high frequency, and water is amazing at that level. Other textures are nice, too.

Social and verbal:
I most definitely always understand what is being said, except if it's a metaphor I may need a clarification. I don't always know how to respond though. I haven't always been verbal. My mind did not form the words at the time, and even now my speech isn't always controlled. I am listening to what is being said but not sure what to say back, or what to do. The speech sometimes feels like it is happening too fast and I cannot make the words. The same thing applies. Certain things that are said sound off, and hearing them is not good.

Aggression:
This is very frustrating. Things around us just aren't controlled, and sometimes it makes me angry. Everything is just moving, moving, going, going and it's too much. So I sometimes I hit myself. Because there is no control in anything, and the only way to make things stop is to feel something intense like pain, so that we don't focus on the weird stuff. I don't injure anyone else but the same thing applies. We are trying to control something.

Emotions:
These are difficult to understand. I understand with my room mate, if she loses her job it isn't good. But I don't completely understand her feeling. I understand the situation is bad. It is hard to tell with faces because it's just not what I look at. I don't look at people' s faces to see what they are feeling. I don't think to. Instead I think about situations or whatever we are talking about. It's not the way it works. I just don't notice.

Being touched:
Being touched feels bad sometimes, like something is on me and it feels strange. It's strange and if it doesn't stop it feels odd too. Especially if I don't know the person, because they touch me and it doesn't make me feel good since they are a stranger. I will hug my room mate because she is my best friend and I like her enough that it's okay. If someone touches me from behind it feels bad. Don't do that to anyone.

Stimming, obsession and repeating words:
This is nice because it has control and feels good. It feels really nice when I flap my arms or tap my chin. The way it feels is good, and I don't pay attention to if people are there. Sometimes I think when I do it, about college or my dog or any thing.
I have a few things I like a lot. Ninja turtles, South Park and Tennis balls. They all interest me, and I don't let other things distract me. Other things that I just don't pay attention to. I also have a superior memory so this helps me record it. Other people maybe don't focus so much on things because they have a whole bunch of little things they think about too, so they don't have time. I don't see those little things as important, so I don't notice them. My mind only focuses on things I actually like.
Some words I hear sound really good, or funny. When they sound this way I hear them over and over because I don't want to stop thinking about something that feels nice. They are really nice to hear and think about. So I repeat them out loud since I am having fun.

Eye contact:
The same as I don't notice what people's faces feel, I just don't think about looking people in the eye. My mind just doesn't. It's naturally not something I do, nor is it a priority. As a matter of fact I see no purpose in it.

Motor skills:
My body is sometimes hard to control . I may want to do something, but it happens a different way. That's just the way it happens, like I walk on my toes because it's how my body walks.

Honesty:
It never occurs to me to lie. I don't think about it, the automatic thought that comes to my mind is to tell the truth. The same is true for telling people things they don't like. Sometimes they get upset but whatever part of NTs mind can make something else to say, it's not there with me. I just say it because it's what I think to say.

Humor:
Some people might get upset with this because they do not pay attention to if the person is joking or not. I used to not be like I am now, but if people I know joke with me, it's okay because they are either joking or being honest. I learned to say something back (my best friend taught me) because sometimes its both honesty and joking. I have my own sense of humor, certain things are really funny because when I hear them, it sounds nice.

Metaphors:
I told you I understand everything people say. I even take it literal! When you say "raining cats and dogs" I always, always picture cats and dogs falling from the sky. But once you have explained to me what it really means, I am able to understand what you are saying, although my mind still sees the animals. So it's okay to use metaphors with me, just make sure you clarify if it's a new one.

Routine:
I said before about things being controlled. Some people prefer sameness in everything, every day. This is because if things are different and out of control, they don't feel nice. Like people don't enjoy doing certain things. I'm not that strict, but I do like to plan. For example, if I plan to go swimming but it rains, this feels bad, because I have already mapped out what will happen, I have already decided. When it changes, control is lost, and that's bad.

Friends:
Most people have a hard time making friends with us because they do not think the way we do or relate the same. I am lucky to have a best friend, and I prefer her because she understands. Since it's hard to respond the same, all of what I mentioned above, other people don't befriend us as often. This doesn't really bother me because I don't want people around who don't understand me. Most likely if they would rather do other things, I don't prefer them either. It's not important, so I don't notice.

Talents:
This is like the other things I mentioned, because we don't think too much on no important things, we are able to focus on things we like and get good at them, such as math, drawing, or foreign languages. Some of us have these talents but we aren't sure how to express them.

The main thing to remember is that we are not "trapped" in some other world. We are on planet Earth with everyone else. We respond and process things different than you, and we may do things that you just don't understand.
Try to make your brother comfortable and do things with him that he likes. When he does something that you don't "get". Remember that NTs do things we would never think of too, like state at someone's eyes for no good reason.
We can learn new things, too. Some, like me, find it easier to type or write than to speak. What will help us most is when people encourage us and let us be who we are. Trying to make the world more comfortable helps too.

If you have any more questions or need more explanations, PM me.