Actually, sugar and carbs are interlinked. If a product is low in refined sugar but high in carbs, it can be a poor choice for a diabetic patient. Some of the so-called sugar-free choices are loaded with sugar alcohols, and these can affect glucose levels and also cause gastrointestinal distress (gas!) for some people. And frankly, a lot of this stuff tastes like crap! I occasionally eat it, but it has a "Frankenfood" taste.
If your friend can eat some fresh fruit (berries are fairly low in sugar), I’d suggest something like that with fresh whipped cream made with Splenda. It’s healthy, it tastes great, and it shouldn’t mess up glucose levels.