FFS!
He took coke a few times, he is hardly a "junkie!!" and nowhere near an addict. Do you have any idea of just how wide spread the recreational use of this drug is?
It's like calling someone who has drunk a few glasses of whisky an alcoholic.
He was far more foolish in terms of blabbing about it and mentioning it in what seems to be a desire to impress, that, far more than anything else, would worry me about his judgement.
Change of behaviour, appearance? Oh please...............
You sound like you are discussing a heroin addict.