what toy(s) to buy 2 year old brother?

It sounds like he's got everything he could possibly need. How about instead of books or toys, you buy him an experience? Take him to the zoo or the museum, or a science center. I took my two year old to the butterfly conservatory (at about 2.5 years old) and she loved it. Plus I got a ton of beautiful photographs. She's now three and she still talks about it. They have a Thomas train exhibit here (Canada) every summer. If he's into Thomas, it might be worth it to see if there's something similar near you. Or check if there's a hobby train exhibit. At two, he's not going to care that he doesn't have a present to open on his birthday. But he will care about having a fun day out.

Good luck!

Edit: I wanted to say that most places are free for kids under a certain age. You'd just have to pay for adult tickets. I don't know how old you are, but you might be able to take him by yourself?

You could also take him to a farm to pick apples or strawberries.