Family Sharing issue

I don't think I've ever been THIS frustrated by an Apple product - been an owner since the clam.

Tried to set up Family Sharing and what would (you think) an intuitive plug and play has been very frustrating and probably wasted most of my Sunday. First, I've had my iTunes set up through Paypal for years now.

Family Sharing should have a warning on the FAQs that it only works for CC or debit cards.

Been on the phone for an hour with support and this was never brought up.

I was setting up Family Sharing on my iMac with Support sharing my screen, after they hang up, I decided to finally try it on my iPad and there found the missing "Set up Family Sharing" button ( iMac kept bouncing me back to "add payment method" instead of rejecting the Paypal account. 2 Support personnel helped me, rebooted my system, signed out/in etc.)

iPad outrightly gave an error message, "Paypal is not supported on this device". Voila, I replaced it with a chip card and I was able to enter family members, sent invites etc.

Then, now I'm on my son's iMac, he still can't view any of MY purchases. Made sure he had all the necessary updates on his computer (another 30 min on that). Followed all the suggestions on this thread and others like this https://support.apple.com/en-us/HT201454 to no avail.

I'm at a loss. Can an actual user please provide me with a step by step as I am not sure what I need to do on my end from my iMac to allow him to view?

I had already done

System preferences

Managed Family

clicked share purchases iTunes, books, apps

On my son's side

His iMac is set to the same apple ID both under system preferences and iTunes, same country/region.

Thank you.