Shadow of Mordor is the GTX 960 killer. If more next-gen console ports are like that (now that last gen is being dumped as a baseline) the GTX 960 (and the R9 285) will go down as some of the worst value cards of all time.
There are a lot of games that smash 960 but certain members on this forum purposely try to not talk about them to hide the 2GB VRAM bottleneck.
For the OP, depends on the settings and games you want to play. If you wanted a future-proof card for 5 years, should have spent $50 extra for the R9 290 4GB - would have gotten double the VRAM and 50-60% more GPU power. I doubt anyone on this forum would have recommended you to buy a GTX960 over the slightly more expensive R9 290 if the discussion was to keep it for 5 years.
A GTX 480 is still capable of playing games 1080p high acceptably 5 years later. But a 60 model, especially a weak 60 model like the 960? That thing will be trash in 5 years.
960 is only as fast as the original 925mhz 7970. In 5 years from now, that level of performance will be
8.5 years old! I personally think 960 will be too slow even in 2.5 years. But if he plays games like SC2, LoL, WoW, CS, DOTA, etc. at low-mediums settings, it could last 5+.