I bought an Apple Music family subscription and added my boyfriend to it, but he is still not able to access it

Can he see the shared plan in Settings ➜ Family?

Is the Apple ID he is logged in at Settings ➜ Account ➜ Media & Purchases the same one you added to Family Sharing?

Can you post a screen shot of what he sees, when you say it is asking him to pay for a new plan?

Can he see the Apple One subscription on his own device under Settings ➜ Family specifically?

If he can, then he should just be able to open the Music App, and access the shared subscription directly in the "Listen Now" tab.

The expired student subscription will continue to show up there, but that has no bearing on his access to the shared one from Apple One. The shared Apple One plan and included subscriptions will not appear for him under his own subscriptions. They should only appear as shared in the Family section of the Settings app in his profile there, under "Subscriptions You have access to".

I’m having the exact same problem, but in family on his phone it shows that he has access to the Apple Music shared subscription, but when he goes to music it tells him he has to join. This screenshot is what his phone tells him in family.