But first - how it used to work. In my family we have 3 iPhones, and before "Family Sharing" I just tied everything into my Apple ID, which meant every app AND every song in my iTunes collection was shared. However, there were some issues with my sons iTunes gift cards and one shared account, so we moved him to a "Family Sharing" account. Solved the issue of gift card balances, and we can still share most apps, BUT we can no longer share our iTunes collections (why? I don't know... probably licensing issues...)
- I created a "family" Gmail account, and connected it to Google Play Music.
- Next, I downloaded the Google Play "Music Manager" to my Mac, and uploaded my music library to Google Play. Google allows you to store up to 20,000 songs in their "Play Cloud"
- Next my son downloaded the "Google Play" app for his iPhone, connected it using our "family Gmail" address, and voila, he has access to my iTunes library again