i am not a herp vet, but ive been in veterinary medicine now for close to 15 years and have owned reptiles a long time now, i have never seen or heard of a true diagnosis of mites causing neurological issue. i have seen mites as one of the rule-out or differential diagnosis in a neurological snake. now, that being said, chemicals that are being used to treat a mite infestation, i have seen cause neurological issues, but usually resolve with time (assuming the keeper recognizes the signs and gets to a vet fairly soon). but i have never seen a legal medical record stating as a single diagnosis "mites or mite infestation"
where im going with this, is that the three things that are generally resposnible for causing continued neurological issues in snakes, temperature (usually too hot in its microenvironment, chemicals (either cleaning or treating for parasites), and ibd.
i would assume that as a keeper, your temps are probably correct. i would say, that chemicals could be a part in it or be causing it, and/or ibd. if its chemicals, it should hopefully stop acting neuro once chemicals are stopped. if it continues and/or gets worse, ibd is highly highly suspect.
all of this is, or course, based on if that snake is actually neurologic and not just laying that way for a period of time
a video, and some handling would definately be beneficial