My son loves a certain brand of granola, which used to be sold with a lot of large clusters. Now it is more of a loose cereal--he has difficulty with fine motor use of a spoon. Can I mix the loose cereal style with egg whites and bake in the oven to create my own clusters? Are there any other techniques or suggestions I should try? 
Egg whites is widely suggested as a way to do this.  I also see honey being recommended.  In either case, don't mix the granola as it cooks, perhaps turn the larger chunks gently, 1/2 way (or more) through the cooking time. 