Tokyo has a point; Al's personal development has been very odd for some years now. Sometimes he still talks like someone much younger than fourteen. (Please remember, he
is just fourteen. When I was fourteen, I was a clueless brat. Don't know about the rest of you. Hey, maybe some of us are fourteen now.
) He has a vulnerability that Ed never had even as a child, which actually seems to have increased over the past four years. He's a kind and gentle person. But he has matured, and he is himself. Al is taller, stronger, more sensible, and quicker at mathematics and such important things than Ed, but he doesn't have Ed's fierce internal drive and self-assertion. Due to being 'hollow inside' the way he is, and his natural personality, he is also in a position to be emotionally dependent on Ed, because even though he's a naturally friendly person, he's got too big a secret to keep to interact too extensively outside the duo dynamic.
Until recently, when they were acting separately; one effect of the current situation he's caught in with Pride is that they're back together and Al needs rescuing. He couldn't quite cut it alone. Ed
missed Al, but his effectiveness isn't cut down too much without him. The fact that Ed is a more significant existence in Al's life than Al is in Ed's (not to denigrate Ed's genuine and immense devotion to his brother) gives a very strong impression to me of Ed as the older. There are plenty of younger siblings to whom their elder siblings are more or less insignificant, but in pairs of siblings with only a few years between them, it's fairly rare.