Take the $500 invest it and create more $ to buy a system that will last him a while. Whatever you scrap up with $500 will not be the latest and greatest and he’ll just be playing catch up and eventually spend more.
Probably best bet is to get a used workstation pc with a 6th or 7th gen i5/i7, add an 8gb stick of ram and use the rest on a graphics card
Even for something lower end you’ll be spending $150+ for just a 1050