I think that he has symptoms of wry neck. The neck can be twisted, or the head can go down or up. Pinpoint pupils and the wry neck sound like neurological signs, and are common with Mareks and head injuries. Vitamin E and B1 are good to give for wry neck, but it woun’t help if it is Mareks.
It also looks like he has lice eggs around his face. Permethrin dust or spray are good for treating lice. If you lose him, it would be good to get him tested for possible Mareks with a necropsy by your state vet. Here is a link for contact info:
http://www.metzerfarms.com/PoultryLabs.cfm