Apple One premier and Family sharing

I’ve had Apple One premier, and a family sharing group for a while now.

Recently my husband said he couldn’t access his iTunes (his libraries were gone, and it prompted him to sign up to listen) I checked that subscription is still working, and family sharing is still on. I checked that my “sharing purchases” is still on.

I saw something about putting my Apple ID as the one listed under the purchases/media tap on his phone. however when you do that our music libraries combine, and my apps become available on his phone. We don’t want to share our music libraries, or my apps that I have under my ID.

Why can’t he access ITunes? Is there a way to use Apple one without sharing our libraries/apps?