Q: family sharing

Hi there
I started family sharing as my son is under 13 and I wanted to be able to keep an eye on what he was doing.  now he hasn't got his apple device anymore and doesn't need his apple id etc anymore.  I can't exit family sharing on my account\devices as he is under 13, is there anyway to maybe delete his account or exit family sharing as his account isn't in use anymore so I am not part of the family sharing?

many thanks