Whenever I give a bike to someone I know, or even sell it to them below my cost, I always attach a few strings. A. You ride it. B. You take care of it. C. If you ever get rid of it, I get first crack at it.

In this case, because it's your little brother, and because your little brother is 6'7" I would kinda ease into it. Try to come up with an alternative bike that would suit him and his size and then suggest a trade. In our family, brothers never get refused.

Nice Raleigh BTW.