[Can’t even go through 1 day.]

Read a good book - Perhaps one about games might be interesting to you?

[Where to post experiment?]

I have a plan to counter phone addiction. Where is a good place to post it? I'd also like people to report their results of my plan.

[He's addicted but doesn't care]

Ask him where he sees himself in the future if he continues like this. Make sure you get a reasonable answer.

Then ask him "Is this truly acceptable?"

When he answers no, then ask him how is he going to change that? If he answers yes, then I'm not sure what next.

Oh, and make sure to pick a good time to ask him. You need a serious answer, and he will need time to think.

Hope this helps.