I know he may appear too old for a chart, he might even comment, Mum I'm not a baby. At that point I would say to him, behave like a 12 year old, you will get treated like one! Do you need me to tell you how the chart works, this is solely for your benefit not mine.
This may have been answered, but is he fatigued at all, so he needs the sleep.
Actually this may be a good way to go, I'm really worried about you and all the sleeping, so we're off to the doctors, they can test your blood and make sure you're ok. If there's anything you want to talk about but cant find the words, write a letter, just so I understand, as your behaviour is worrying, I want to get you the help you need.
If you've a diary or even on your phone keep a track of the incidents to see if there's a problem.
Is there anyway his Dad could get in touch? Like social media? His Dad or a friend / family member could be stirring the pot as it were.
Sorry you're having to go through this