Ok yeah that is way too much hairloss. He needs to see a vet. That's extremely unusual. Mites are microscopic. You can usually tell your animal has them when they're itching and losing hair. See a vet.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry