I'm sorry that you have to see your precious grandchild I this situation but it is wonderful what you are doing by letting him stay in your home. As long as he is not threatening you or a danger to yourself or others, it is great he is off the streets. You probably know if you are enabling him and I would agree that this doesn't help him in the long run. If the situation changes, don't hesitate to call a CIT officer to come and take him to the hospital.
As you know many of our children have drug problems. Even marijuana keeps the medicine from working like it can.
We are also at a stage where we need to get a case worker and have them come to him. Great advice doctor.
I'm glad you found this forum. Keep us posted and take care.