I would tell the guy to call his doctor and ask if there is an antibiotic that would do the same job for less. From the little bit of reading that I've done, it sounds like they went straight to the vancocin, when there is a cheaper antibiotic that is usually the first resort drug for this issue. Getting some good quality yogurt, and eating lots of it would help rebalance the guy's gut flora; something I always start as soon as I start any antibiotic.