For the given budget there's probably only GTX 750Ti 2GB from NVidia GPUs that is worth considering for ED. However, AMD R7 265 might be a slightly better option performance wise in the same price range with R9 270 being slightly above the price given price limit. But I would seriously consider investing $50 more for GTX 960 if it is possible or AMD R9 280 as these two would give you some head room for the future.
If he has an AMD CPU then the AMD R7 makes sense. With the Intel CPU, it's a coin toss.