Based on his white hair is he an old altmer


He clearly has 1 agent that he contacted but did Elenwen know of the eye?

Well, Altmer tend to have blonde hair. Blonde hair turns white after a while. Seeing as an average mer is considered old at the age of 200 and very old at the age of 300, I don't think he'd be that old.

As for Elenwen, I don't think she knew, or at least, she didn't know of his intentions. Ancano wanted to unmake Mundus, but the Thalmor just want a new Merethic Era.

I doubt very much Elenwen knew about the Eye. One advantage of the College is its isolation makes getting messages in and out difficult, and Winterhold lacked the dock facilities to bridge the distance between Winterhold and Solitude.

There's also the fact Ancano was operating as a rogue agent, so it's doubtful he'd tell Elenwen about the Eye.