I'm running an AM3 FX-4300 CPU at the moment while my Ryzen is away in the hopes of getting an RMA..
The motherboard is an ASUS M5497 Pro
RAM is Corsair CMZ8GX3M2A1600C9
You can find compatible 2nd hand motherboards and ram on the bay and other 2nd hand sites but......
....This is a 12 year old machine. It's only good for browsing the internet. Gaming is nigh on impossible. So, as Earnhardt said, it would probably be advisable to try and persuade your friend to go up to AM4
If you really want to stick with that CPU, google AM3 motherboards that are compatible with the FX4100 - find a motherboard you want, then check it's QVL list for compatible RAM.