I had the same issue with adding my dad (inviting him and adding were successful, but he could NOT access any of the family sharing music), BUT after searching the internet for hours, I just found the answer on Reddit and this solution seems to work for a lot of the people who posted on it.
Do not have your husband sign up for his own trial or individual subscription.
If you see him in your family sharing, then from your iPhone, go to âMedia & Purchasesâ under Settings (from Setting, clicking your photo/your name - the 1st line in Settings). After clicking on âMedia & Purchasesâ, a menu will pop up. Click on RED âSign Out.â You may have to try to sign out a few times. Then sign immediately back in using your Apple ID login and password.
Doing this will reset your connection to the subscriptions and recognize your husbandâs acceptance to your invitation to Apple Music Family Sharing!
Also, FYI, per Apple Policy, you have to be in the SAME REGION as your family member or friend you are inviting to Family Sharing. BUT you do not need to live in the same household.
I hope this helps!