Family sharing issue

My 11yr old som had an iPhone 6 and was part of family sharing. We gave him our spare iphone7 plus - switched the SIM card over and he was on our family sharing. Well he wound up breaking the 7 so we moved his sim back to the 6 and that’s where the problem begins. On his phone is his family sharing info from the first time he had the 6 - on my phone is the info from family sharing when he had the 7.

How do I get them to sync so that the family sharing is correct on both phones and we can monitor his usage etc? His Apple ID is blocked out on his phone as well under settings.

thank you

Sean