I would imagine that lod though you were using some drugs, and the smell of aftershave was to disguise the smell of drugs. However, it seems that he was being over zealous, and I wonder if he asked your names etc? Did he do a PNC on the car, and check it was registered to your old chap? If it was me and my son, I would be down the nick pronto, asking questions like the above,, and registering an official complaint.
If you are in the front seat, you are technically in charge of the car, but as far as I am aware, smelling of Brut is not yet an offence, and the copper was just being a pillock.