Well in America, no one can cancel another person's visa other than the one who's name is on the visa. So, no your friend can not cancel his wife's visa.

One must ask the question, tho...does the wife WISH to leave America(and her husband) permanently or is this just the wish of the husband to rid himself of his wife? In order to do that, they would have to get divorced, if I am not mistaken, then go through the paperwork in person.