I wrote about the same yesterday. Prevention is always better but if it's too late, understanding addiction is important before you go grabbing his phone and throw it away in a reactionary way. Addiction usually comes as a consequence of something else wrong with your life - could be your "friends", school/home or expectations.

I remember it was hard to make friends with similar interest in school due to the secluded rural area. I couldn't fit in and I wasn't willing to (parenting might have eased here). I had "friends", everyone believed that and I did too but I didn't interact beyond the usual classes and was isolated emotionally. It was hard to open up and I resorted to online silos where I could talk freely and was emotionally rewarded. It was addicting because even if I had friends irl, I wasn't getting any reward from talking to them. My brain didn't register it. I didn't like them but I couldn't move places or have new friends somehow that were more aligned with my interest. It was an inevitable escape.

[1] Role of lifestyle in substance addiction

[2] Problems arising from smartphone addiction

[3] Alternate to blaming smartphones for addiction

[4] General overview and tips on smartphone addiction

1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4326198/

2) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6449671/

3) https://www.frontiersin.org/articles/10.3389/fpsyg.2018.0014...

4) https://www.psychologytoday.com/us/blog/reading-between-the-...

self plug) https://notably.cc/#/note?id=oz9fMjsOa

Edit: Tried to make links descriptive. No markdown for links :(