Guardian? Is Grens underaged?

Gren is younger than shin but even so when you enter into rehab or mental health facilities you have a guardian put down just in case of emergency, death, etc.

So he was taken to rehab ??

Oh, I see, I wasn't thinking of this possibility. Well, I hope he stays there, under the radar and gets rid of his addiction. Somehow I wouldn't like him interfering with Jake's plans.