AMD is way behind the curve on performance which is why I stayed away from posting tech that is that old. As an upgrade, it would not be worth it.
I updated my post, but still the original CPU I posted is a Phenom II AM3 socket, it's not that old and sounds like it would suit his needs well with the Radeon 4870. Will blow him away compared to his current system and sooo cheap. You can spend 2 or 3 times as much but I guarantee your computer won't be twice as fast. Well unless your just going to be encoding video all day.
I'm running an old intel 2160 1mb (clocked up to 3.2) and see no reason to upgrade yet because most current gen games are more bound to the GPU, so put more money into that.