Soft stool in rabbit but not runny should I be worried?

I don't think it's a symptom of snuffles. Snuffles is very similar to our common cold. Is he only doing this at night? If so it could just be night copulation which is perfectly normal in rabbits. Make sure that you aren't giving him any fruits or veggies yet because those do tend to cause diarrhea in young rabbits. He shouldn't be getting any fruits or veggies for about another month. You can treat it by giving him a little bit of oats every night. Rolled oats, you can get the at the grocery store they are relatively inexpensive. Make sure the ONLY ingredient is rolled oats, we usually used the old fashioned rolled oats. You could also give him a little bit of grass hay to nibble on. That seems to help too. But don't give him any fresh greens/grass, and don't give him alfalfa hay. It's too high in protein and a young rabbits digestive system is very sensitive.