Scotch for a Cognac Drinker
My suggestion is to marry what you know about his knowledge of whisky with knowing he drinks Cognac. The easy answer is Isle of Arran, Napolean Cognac cask finish, if you can find it. Wine-searcher.com shows Park Avenue Liquor in NYC still with some - it was a limited edition bottling. They list it at $80 USD. Also, Arran's whiskies have generally received quite high marks from the critics and press since their first release, so you can feel confident you're not just giving but giving good.