Guess it depends. Has he/she been having acne for long? If so and if products (though alot of them are pretty crap) arent working, then asking a gp/doctor what they reckon would be a good next step. Have you thought about him/her trying benzoyl peroxide? Thats usually pretty good.

Speaking from experience I would suggest doing all you can to solve the problem naturally i.e. Diet,vitamins lifestyle changes etc before you consider antibiotics...while antibiotics will most likely eradicate the problem in the short term as soon as the acne becomes resistant (which it almost certainly will) or you stop taking them the acne will return and most likely be worse than before. I tried 4 different antibiotics and the same happened every time. All that was left was accutane so instead I changed my diet and tried some vitamin supplements and while my acne is not cured it is 100 times better and manageable without having to take any more antibiotics.