R7 240 is the fastest, But the gtx 650 or ti is around that price range, you should at least check one out, it would be a major step up from a R7 240
gtx 650 is no were near the r7 240 in price .
r7 240 is 70$ and the gtx 650 is over 100$ and gtx 650 ti is 150$.
at the price of gtx 650 ti he can get a r9 270 which is far superior than these cards and at the same price of gtx 650 he can get the r7 260x much better than gtx 650 and gtx 650 ti.