Help.

without jumping through all the hoops

You must jump through all the hoops 🤷‍♂️.

created a new meta account to put his age as 17

Bypassing child restriction by putting in the wrong age could lead to the account being banned if/when Meta AI eventually detects it. That would mean losing any purchased games owned by that account. Just letting you know.

But now it is saying the game is almost 30.00 instead of free.

Purchased games/apps are associated with the account that owns them. If a new account is made, the games cannot be transferred to the new account.

linking it to my Facebook

I don't recommend linking your Meta account to Facebook, Instagram, Whatsapp, etc. If you FB account gets banned for whatever reason, all your linked accounts get blocked, and you might not be able to use your headset.

But he doesn't have Facebook. It would not let him do it.

Send the invite link to your own email address. Open the email and enclosed link on a PC. That should work and allow you to add the 13+ child account to Family Center and the headset.

What do I do?

It's not clear which account "owns" the walking dead game, but I'm assuming it is either your account or your son's original 13+ account. Probably you "gifted" the game to the 13+ account?

You must set up the headset using your (parent's) account. Then add the (correctly set up) 13+ child profile. Then you can set up App Sharing and share games from your account to the child account on the same device. In the actual headset using the primary account, under Settings->Profiles, select the toggle "share apps on this headset". Then install the games you want to share (ones that your account "owns"). They will now show in your child's library when they use their child account on the same device, and they will be able to install them once parental permission is granted. Note that any games that the 13+ account already "owns" (such as gifted games) will be available in that profile's library, but they cannot be shared with the parent account.