@DeborahW_792768 I've managed to find an app called Boomerang that may offer what you are looking for https://useboomerang.com/#prices (shows details of Apple App Store and Google Play at bottom of page. No idea if it's any good.
Other alternatives include:
1. Take phone away until he can assure you that he will meet your rules.
2. Assuming that he is at school, discuss with staff there - they usually have policy to cover the school day.
