This is a real serious problem for dogs -----sarcoptic mange; The scabies mite that attacks huimans is a different one. Dog mites dont like people,
Its no good cleaning just the carpets but should include all of the soft furnishinsg and bedding . using mattress cleaning techniques with UVC . You will probably need to do the treatment again after a fortnight or until the problem is solved.
You may have to spray as well.
Ensure full contamination protection if you work in other pet homes or have dogs at home.
Also make sure dog(s) is being treated.
This is not a quick job. Sadly many dumb people prefer to keep paying the vet large amounts of money rather than get a good cleaner to sort out the problem.
Demodex mange is more seriou s but less likely. They will need to learn how to treat and clean the dog
If Its human scabies...... offer them a mattress clean as well , if you are brave, or just walk away if you have kids at home, or granny --less hassle.....
In humans there is a chance that it is really something else anyway. I had dermatitis once that the doc said was scabies.