What drug lasts for over 16h

Long story short: stepson (16m) came home yesterday from friends and was clearly high. I didn't see him and wife didn't tell me yesterday. I didn't see him until noon today and noticed there was something weird about the way he acted. I spoke about it with my wife and she said he admitted to her that he had been smoking cannabis yesterday. He came home by train and missed his stop in our city, so my wife had to drive to the next one to get him home. She had the conversation in the car in which he admitted on smoking cannabis. I simply don't believe a cannabis high lasts over 20 hrs. So my question is what he might have taken. We're really worried what it might be.

Symptoms: he acts sluggish and apathic. He also doesnt know himself it's so obvious for his surroundings that he's still high.

Edit: He just told my wife it was hash. Could this explain the longer high?

Edit2: 3 hours and still not ok. Some extra information: he has an 11 yrs old sister in the house. I don't mind experimenting a bit, but this is scary.

Edit 3: Thank you for all who were concerned and gave some good advice. We don't mind that he's experimenting a bit with weed, but we were just worried about how he reacted. He has a low self esteem because his father threw him out a year ago and we don't want him to numb out his world as an escape. Because of what happened, he's in a vulnerable state. Besides that, he missed his first three days of his exam week at school. So people here who are parents, will understand what we're going through.