The problem with a sliding scale is that it doesn't take food into account. Did she also tell him what he should eat at each meal? If one day he has bacon, eggs and one slice of toast for breakfast and the next he has pancakes & syrup those meals will require vastly different amounts of insulin. I believe carb counting makes the most sense. The thing you have to watch for is stacking insulin. Humalog lasts around 4+ hours in most people so if he does a lot of snacking or smaller meals he could be stacking insulin. I would also make sure that he doesn't do any corrections before 4 hours unless his BG is really high.