Skye is right. There is a type of reflux called "silent reflux" sometimes babies get it.
Jfarel is correct as well that the reflux meds can help with digestion. What happens in people with CF is that our gallbladders are exceptionally small (many in fact have atrophied) and as a result we cannot properly regulate the bile that comes into our stomach from the liver and stuff. When the acid gets into our stomachs, it is too strong for our enzyme supplements to withstand. Our enzymes are supposed to be absorbed in the small intestine, not the stomach. That's because the small intestine is where the nutrients are absorbed.
Long story short, acid reflux meds cuts down on the acid in our stomachs and gives us a better shot at absorbing not only our enzyme supplements, but the vitamins and minerals from our foods.
I used to think "why bother taking this? I don't have reflux!" but since I've been taking it over the last year, my weight and absorption has improved DRAMATICALLY.