Sounds like he shorted something when he was installing the new components. What did you end up giving him that he was installing?
If he bought a new power supply make sure he uses the cables that come with the new power supply instead of reusing the old cables already in the system. If it's a modular power supply it might be tempting to just unplug the old power supply, slot in the new one, and plug the old cables back in so that you don't have to deal with redoing all the cable management. DON'T DO THAT. Mixing modular PSU cables can kill components.
I gave him some new DDR 3 RAM and an RX 550 graphics card. Also a Sound Blaster audio card and Samsung SSD I doubt he installed.
The old PS was 10 years old and not a particularly good one. He has an even older one to try to see if it powers up. If so, He can R&R it with the new supply. But if it cannot power on? He accepts he needs to spend about $300 for a Ryzen 5 2400g, 16 Gig DDR 4, and motherboard and we go from there.
I will let him know about the power cords (It will be a semi-modular so, he needs to avoid this issue). Thanks!
GOOD NEWS: He just messaged me. He put in the new Power Supply and the PC boots up, sees added RAM and RX 550. I asked him to try to get me some FPS counts just out of curiosity. Thing is, most of my family members cannot wind a watch without massive help. This kid took the parts I gave him and figured it all out. May be hope for the future!