Inorder to interact with guys generally, inorder to date one of them and inorder to marry one, it is highly recommended that you have some understanding of what you're getting into.
Now, inorder to explain to you what you're getting into, I'm going to have to generalize. There's nothing wrong with this, so long as you realize that there are exceptions and that life is not always tidy and you should not clutch at any generalization however accurate it might be as though it were a theorem out of Euclid about triangles having 3 sides. Triangles always have three sides. Guys are not always the way I'll describe for you. But they are usually that way. So budget for exceptions while at the same time expecting my descriptions to come true right before your very eyes.
Guys are simple, in a way that women are not. Consequently, you will be tempted to over-analyze everything and you're accustomed to things being complicated. You have adjusted to those complications and you think they're normal. You think that guys are doing the same thing. You analyze his brief comment, that comment with a thousand possible meanings, when it was just a brief comment. When I say that guys are simple, I'm not saying that they are stupid. They're very intelligent and can win wars and send people to the moon and build smartphones and so on. But their intelligence runs on a very different operating platform than your intelligence does.
As a general rule, guys think of one thing at a time; like a dog pushing a rock up and down the sidewalk. Breakfast breakfast. Commute commute. Work work work. Lunch lunch. Work work work. Commute commute. Dinner dinner. TV TV. Sleep sleep. Repeat repeat. If you ask them to do more than the one thing they are currently doing, it annoys them. Women can generally do three things at a time, think about two things, talk on the phone about another thing, and all with a baby on their hip. This is a grand mystery. But it is also why meat, and peas, and the mashed potatoes all arrive at the table at the same time all of them hot. Now, these examples assume a married couple.
But suppose you have these two different ways of thinking, still single and in the process of getting together. Think of this as a divine sense of humor thing. They will both have very different perceptions of what the heck is going on. When a man decides that it is time to pursue a woman, he's doing the next thing. He knows he needs to be married and so it goes onto his to-do list. Men think in a linear way, one thing at a time. Women are lateral thinkers and can run multiple tracks at once. One of the problems will be that of assuming that he's doing the same thing that you would be doing when he's doing nothing of the kind. You will be like a master chess player at a game with a novice. When the novice makes some random move, you will think of three different ways that could be an uncanny genius move. But it isn't. It is simply what he did and it seemed like a good idea to him at the time. If it is outside their realm of experience, the fact that men are such narrow linear thinkers can be mistaken for stupidity.
You bring up something perfectly reasonable like the fact that he asked you out on the three month anniversary of your first date to the day, which you thought was so sweet and he just blinks at you dumbfounded. He actually asked you out because you already went out on Monday and Friday comes after Monday. That anniversary thought never entered his head and not only so but it never occurred to him that such a thought could ever enter anyone's head.
So one of the things you'll have to get used to is the fact that heterosexual relationships are always cross-cultural bilingual situations. You come from different worlds. He's a guy. They do things differently over there. You must make room for that. Do not make the mistake of expecting him to make room for the way you are while at the same time not making room for the way he is. Meet in the middle. That's what sensible people do!
Your brother.