He has just started sixth form.
Out quite a lot recently. Room smelling of weed, sometimes his clothes etc. He doesn't deny he's tried it at a party or whatever - but says its because mostly he's around people who smoke it or on occasion he is in the same room with them.
Anyway, sick of the horrible smell, it sometimes seeps out into corridor, though I have to say I have got a sensitive sense of smell.
Nothing I can do though is there? What do you think?