Is that the tail of some strange insect sticking out of his ear?
Ewwww!
It's probably a hearing aid. He needs a better one, it would seem. He needs a better reading aid (aide?), too, evidently.
That said, if that is a critter like the worm from Star Trek II, it would explain some things. Booker was at one time almost reasonable. Maybe we should be checking a LOT of people. (There are many sci-fi references!)