Yes...ivomec him. I give .1cc IM, but you can give it oral also. It takes care of external and internal parisites. If he has lice and mites, good change he has others. I would worm him ASAP>
You can get it online, it is made for cattle, comes in a suspension. But with this situation at hand, you amy want to check a local feed store. I am going to assume it is not cheap because most of it comes in large vials since it is made for cattle. This way you can get everything in one shot. Otherwise you may have trouble getting "traditional" or more natural wormers (like DE) into him and they may not get a change to work before it is too late.
With you lived closer, Id share mine.
Oh, worm everyone, obviously.........