I stopped using my X1950 XTX in late 2008, which was when I bought my 4870. At the time, too many games were starting to run too slow on 1950. 4890 is still good to this day, as long as you aren't running high res/settings.
I'd be surprised if he could even get half playable framerates on an X1950 XTX.
I tried running one of the recent need for speeds (forgot which) or was it a Spy Hunter game? on an X850 on my pentium 4, and boy was that torture.
If he still has an X1950, he REALLY needs to upgrade. He can grab something that will run those games, without the infamous x1950 bugs, for not much more than the price of a full cost game. If he's buying games, he should have enough money to upgrade...
If he's pirating games, well too bad.
And yeah, a 512 mb 4850 is very cheap now. You may even be able to get a 1 gb one for cheap.
X1950 XTX is over 4 years old now. You can't expect it to run the newest stuff. And about backwards compatiblity, the X1950 XTX is the last card that supported full backwards dx6/7/8 compatibility (w buffer, etc). Both ATI and Nvidia stopped support for pre dx8 stuff a long time ago (Most DX8 stuff still works).