I'm not sure whether this is possible for you (him) but in Canada where there is no payment required, the best thing to do in this case would be for him to go to the hospital and ask to be admitted into the Psych ward, where he would receive all the care he needed. I'm sorry that his parents seem to be so unreasonable. That in itself can have a huge impact on him no doubt. However, he is 15 and should still be covered (hopefully) by their insurance, that would allow him to access a hospital's psych ward. I actually had to have my husband admitted into a psych ward at the hospital, because he couldn't sleep and it caused bouts of paranoid schizophrenia. He was placed on a 72 hour hold, but ended up staying for 10 days while they worked with getting him on "Seroquel" that allowed him to develop proper sleep patterns. Lack of sleep can cause huge problems for a person. I really think this would be his best bet for getting himself feeling better. I'm here if you need to talk.
The fact that he is angry at you for falling asleep and not texting him back immediately is justification for you to walk away. Best wishes - he's a mess, and he's not a mess you caused.
Honey, you don't have to keep trying to help him. He's not your brother or your son. He's someone you have met, and you have the right to walk on past and not be responsible for him.
I know you have a soft and tender heart, but you aren't required to do this. This relationship will suck all the life and joy out of you.
He's 15 and you are 16.
Can you seek help from your school counselor?
Thats so so so sad. I cannot stress enough this is not right at all. He needs serious mental help and i feel hes a danger to you. Go to his school and talk to the councellor there talk to his teachers get him help right away. The school cna help if the parents wont.