It can't be that old, he's only lived here three weeks!
He's been staying in his brother's room (17yo brother lives full time with their mom and only uses his room at our house occasionally).
And he won't even TRY to pin it on his brother, 21yo knows that would be ridiculous.
And we cleaned out difficult child's old room back when he moved out a year and a half ago, and it has been repurposed, so can't use that as possible source.
Dad has warned him several times about not using/bringing drugs into the house. I have been suspicious, but dad has been sure he hasn't been using. Even when dad found a 'corn holder' (the thing that you stick in either end of corn on the cob to hold it while you eat it) in the room with some kind of residue on it.
As for what we are gonna do about it: Not 100% sure. Dad is at work and difficult child is out 'job hunting'. They will be back at 5pm.
It has to be either drug rehab or out, though.
difficult child's mom says she has a plastic grocery bag stuffed full of spice packets from his room when he lived with her till July. They may confront him together.
Of course, mom had made him go to drug counseling at the end of his time with her, but he didn't stick with it, so I don't see out patient counseling as a good solution.