Your AGP slot is v1.0 and operates at 1x/2x speed. You should not upgrade any part of your pc. There would be no benefit whatsoever. The best thing you can do is have it recycled and perhaps get an Atom based system for a replacement.
1. That is only AGP 4x/8x compatible AKA AGP 2.0 or 3.0.
2. There wouldn't be any performance improvement from that card whatsoever on a system as old as this.
3. If he tried to install it odds are his power supply would die from the stress.