I think I'm still riding an entry level bike. That doesn't matter to me though, it still gets me where I'm going. Essiemyra, your brother should be able to figure out what needs to be done pretty quickly, but he's going to need some specialized (not the bike brand) tools to change parts of the drivetrain. He'll be familiar with the idea of what quality tools to buy, and a trip to the bike shop with your brother to see what tools he may need would help.