Sorry for your loss.
Yes, you need to disband the family.
Whether the music is lost or not, and how to minimize the risk will greatly depend on where this music comes from exactly.
If the music was downloaded from the Apple Music subscription service, then when you discontinue the Music subscription, it may be lost. You can minimize the risk, by starting an Apple Music subscription yourself on your account before disbanding the Family Group. That way, when you leave the Family Group yourself, you will maintain your own library. You can then invite the other members of the Family group to your new Family Sharing group, and if done correctly, the change should be immediate, and no music should be lost.
To start your own subscription, open the Music app on an Apple device, computer or Android device, go to your profile, Manage subscriptions and choose an individual subscription from there. Make sure your husband's account still has a valid payment method for now.
Once the individual subscription has been activated, you can choose to leave Family Sharing yourself.
Then make a new Family sharing group as the organizer and invite the other members to it. They should then be able to leave your Husband's Family Group and join yours.
If the music comes from somewhere else, and was synced to the iPhone from a computer, or from a different service, then it should not affect it.
Once everybody is joined to the new Family Group, you can cancel everything on your husband's account and terminate if you need to.
Do note, any purchases and apps downloaded through his account will be lost if you delete the account. So make sure you are ready to purchase anything he bought again if you need to.
click here ➜ Leave Family Sharing - Apple Support
