One thing that always works for me is a pair of freshly boiled eggs. If you have quail eggs, it might work even better. Boil the eggs, wrap them in a cloth (I use a thin washcloth) and apply to his nose closer to the eyes (now, try to avoid the eyes and make sure the eggs are wrapped securely so they don't burn the skin!). By warming up the nose, you will help the air passage to open up. If in doubt, try it first on yourself so you know how to work it around.
I would also recommend a saline solution to moisturize the stuffy nose and a good nose aspirator (BabyComfyNose Nasal Aspirator is great, as well as Nosefrida The Snotsucker Nasal Aspirator; the rest of them are junk). After the nose is cleared up, I'd apply a drop of olive oil in the nostrils to protect them from drying and crusting at night. Olive oil is very healthy and soothing by nature, so it's perfectly safe if applied gently and sparingly.
I hope this helps!
at 5:13 AM on Nov. 26, 2010