To remove smell, one can also rub the hands against stainless steel (e.g. a knife blade, but don't cut yourself). Sounds ridiculous, but it actually works.
I've found a "stainless steel soap bar" (no kidding) in a kitchen store, to get garlic and onion smell off the hands. I was less than ready to believe that would work, but surprisingly it does. (Haven't tried with weed smell, but works with garlic and that surely is a very sticky smell.)
The smell will stick to the clothes, he would have to change. Painters suit is more convenient in that case I would say.
