Sounds like storeowner is incorrect IMO. I have a friend who successfully hatches redfoots every year. He keeps them on moist substrate until they absorb their egg sack. I have never heard of sphagnum being toxic and am pretty sure I have seen it being suggested for baby tort bedding. If the baby is truly a new hatchling, then it may be just chilling and absorbing yolk sack. I babysat some of my buddys hatchlings a couple of weeks ago and was amazed at how little they moved. Just make sure they stay warm and out of drafts. Apparently when they finish absorbing their yolk sacks they become more active and search for food when they get hungry. If this is not a new hatchling, then the lethargy and eye condition may be infection related.