The 210 and 6450 are more like productivity based cards, but if he is not doing any gaming, they aren't bad choices.
I have a 8800GTX on my 4600+ and it bottlenecks alot some higher end games (hey a bottleneck is better than no graphics at all), but that runs alright as well. A nice power supply is required for that one though.
Of those choices, the GT430 or a GT440, like mentioned above are nice. The 6570 or 6670 are also nice choices.
If the friend is not gaming, the GT430 is the best choice, since it would have a lower price.