I think he has a good chance of finding ways to slow down the aging process and buy us some time, just like we've managed to extend lifespans heavily through other advances in medical and related technology. However, I have very low confidence that that direction of research will manage to completely solve the problem. We have far too many ways of breaking down, and not all of them seem solvable by patching. I have somewhat more hope for a solution from the AI camp, personally. I just hope the Uncomfortable Truths Well (http://xkcd.com/568/) doesn't prove correct.