Preventing 13-year-old from downloading apps previously downloaded 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?
You have to go into restrictions and take away their ability to install all apps and blocking the App Store. It’s a pain, but it is the only thing I’ve found that works. My son got ahold of his phone when the restrictions were off and got an app I didn’t like. Even when it was back on to where he had to have me “approve” new apps, it didn’t stop him from reloading the offensive one. Only restricting access to the App Store and all installations worked. Now if he finds out about an app, he has to hand me his phone.