My 13-year-old had an Apple ID before family sharing was available. In the span of a few days he had downloaded a bunch of messaging apps on his iPhone that we, the parents, do not approve of. We deleted them and instituted family sharing (to require approval of app downloads), but it still allows him to download these deleted apps because he had downloaded them before.
How can I clear out the previously downloaded apps so if he tries to download them again it will require him to "ask to buy?" Also, there are some downloads that are on his phone that I believe he found a way around family sharing. Is this possible? How can you prevent it?