I don't know if I have an advice that will help or not...but here is my take on it.
Every time he sneaks out or doesn't come home, call the police and report him. In our community, once you make that report, even if he returns home, you have to let the police know, and they come and take him to juvie. They will probably release him to you in a few hours, the first couple of times. Our juvie department will drug test them, a quick test that they get results in 5 minutes. They will tell you if he gets a positive for drugs result.
Your child may or may not get a court date set up... In our community, the second time it happened, our child had to go to court. She got 6 months of community supervision. Had to see a probation type officer, they set curfews, and when she broke them, she had to do community service, helping prepare meals on wheels.
Once they have a "record" go to your mental health facility and ask about applying for an SED waiver based on the child's needs. They can qualify for a medical card to get more services and a case manager, counseling, family therapy and group counseling. This will be covered by the SED waiver.
The case manager will likely meet with the child for an hour a week. Our teen enjoyed the case mgr meetings, they went out for a treat and talked. The case manager becomes a liaison between school and community corrections and you.
It is better to be proactive than to let things go downhill. Once that happens, the authorities might look back at you as not trying to control your child. Like if he runs away for a couple of days, gets in legal trouble, and then they wonder why you never reported him missing.
This isn't a quick way to get him out of your home...but, if he gets taken in to custody, and they want to release him back to you, you might consider dragging your feet...by saying you don't know that you would be safe (if that is true) or that you are not able to control his behaviors. Then, my understanding is, they would have to keep him until a judge has him in court. That is suppose to happen with in 48 hours ( not including weekends) for the judge to make a decision.
We took our child home when they wanted to release her. Then it was 6 weeks before we heard there was a court date...and another month for court...
It helped to have an outside party help enforce rules...
KSM