Law is not really a career that travels well.

I'm not a lawyer, but I guess he'd have to do Swiss post grad qualifications (what ever they maybe) similar to the UK LPC. I'd think a bigger barrier would be learning German/French to a high enough level... for Law your language would need to be spot on.

Alternatively I think international corporations have "in house" lawyers, who might work in English and in non-Swiss Law qualifications. However I guess it depends what type of Law he is in.