Blue Hair or Grey?

So this passage from the Winter Runes:

Eventually Leopold calls the group to him. He is an old gray hair, who still commands a stout frame. He wears a magical chain shirt and has dark, blood stained leather breaches. He leans on a Halberd. 

I started to change it to "blue hairs" but suspicion that that is a term that has gone out of use by anyone other than me and a few old people.  Of course it doesn't mean Katy Perry. . . .