By Birchas Kohanim there is a Tefila for people who had bad dreams. What does a Kohen do when he has a bad dream as he can not say the Tefila during Birchas Kohanim?
How about this? See Orach Chaim siman 128, seif 25, that where there is a shul consisting entirely of kohanim, and there are more than 10 in the minyan, those who are more than 10 go up to duchen.
So, have him assemble a bunch of his kohanim friends, let him stay as one of the 10 who don't duchen, and then he can say this tefillah.
Not that I endorse worrying so much about bad dreams.