What I have learned with my kids is that where they WANT to go, and where they are happy is what gives them the best path for success in college. That being said, one of the huge benefits of going to MIT or Stanford is that many of their classmates (friends) will go on to found/start tech companies, and I have seen that work out extremely well for a few kids that went to those schools.

Purdue is one helluva school, regardless of degree. If his brother is there, it might help make his transition easier. Good luck!