I took my puppy to the vet and was told he had sarcoptic mange. Could it be misdiagnosed?

The vet said at first he had demodex. After a skin sc she said it was sarcoptic. However my other dogs are showing no signs and neither are myself, children,or husband. Is it possible she was wrong? The puppy is not loosing hair and is a bit itchy, but I bathed all dogs in lime sulfur solution which may have dried out their skin. If it is sarcoptic how can I get it off my furniture and carpet. *Note* I have suede furniture. Also how many treatments will it take to rid him of this. I contacted the breeder and her vet and all other puppies tested negative as well as mother and my dogs as well. He has had the dip and Revolution. Thanks for all help as I have never dealt with this. Oh, he is a Shar Pei and is prone to sensitive skin as well and 10 weeks old. Thanks!