No, not the whiskey. This character is a "white-haired man in long, flowing silver robes" (23.69), and he comes through the gate from Avalon at the very end of the book to talk to Laurel. As a faerie, of course, he's good-looking (for an old guy):
His voice was too sweet, too musical to be of this world. He walked toward her as if he were floating on air, and the face she looked up into was so beautiful. He seemed to glow, and his eyes were soft and blue and surrounded by wrinkles that fell […] in exact, even folds perfectly like hung drapes. (23.72)
He kind of sounds like a faerie version of Dumbledore. And like Dumbledore, when Laurel tells him about what happened with the trolls, he's super kind and understanding about it. He tells her: "you were made to heal, not to kill. I think I'd have been disappointed if you were able to kill someone, even a troll" (23.81). He's a little mysterious and all, but it's clear that he's part of the group that planned to plant Laurel as a human child with her current parents.
He totally gives Laurel a hug when she says he doesn't think she can be what the faeries want her to be, since her father is dying and her mother is desperate. He reminds her that she's one of the faeries. too, and assures her, saying:
We are here to assist you in any way we can. Our aid is your right—your heritage. (23.85)
This is when he gives her a potent healing elixir that can (and does) save her dad's life, as well as a golf ball-sized diamond to offset the medical costs. When he says goodbye to Laurel, he also says that he hopes to see her again soon. We feel a lot better knowing that Jamison has Laurel's back.