I'd be against swapping out the AM3 board for anything, as the FX-8350 will constrain non-esports titles under 60 FPS even with a fire breathing overclock. Something like this $370 USD build with a 3100/3300X/2xxx 8 core if there's any deals on them, 5600 XT/2060, and maybe faster RAM if there's anything left over with case and part reuse (note: AM3 and AM4 have the same CPU cooler mounting if they have a tower style cooler or anything bigger than stock) would give more FPS
Thanks for your answers.There is nothing worth keeping and can keep in his old build, so he will have to build new.