How do I remove a deleted child account from Family Sharing?

My child had two iCloud accounts. The primary one was transferred to our other family plan.

I requested deletion of the old account via Apple. Received confirmation code.

Now, I cannot remove his old account from my family sharing plan? How do I do this?

It’s currently a catch 22 because I cannot remove his deleted account or transfer it. Therefore, I cannot disband my family sharing OR transfer myself to the new family share plan.

Thank you for your help in advance.