Jenn, it's not laden w/ the many things that cause sensitive tummys to go ary. I would have to venture a "Yes, he should be just fine" on this one. There are a few other formulas within the Natural Balance family that you could get other than my fav. (The Original). They make treats out of the soft logs that you can buy (made from the same stuff as the dry kibble), I'd buy a small bag of those treats and see how he handles it. I use that stuff for my tracking bait too!
The blender idea is a fabulous one!
One last thing, you can't get Dick Van Patten's Natural Balance at PetSmart. Only PetCo (out of the chain stores like it) have a contract to carry this brand. Otherwise you'd have to go to a smaller mom and pop store or a feed store.