If you have the option of a duty free whisky, perhaps consider the Lagavulin 1997 Distillers Edition? I personally prefer the standard 16, but it is something a little different for him with a big sherry hit aswell as the peat.
One of my favourite Islays that i only discovered recently is Kilchoman Machir Bay. It’s only a young whisky but imo is as good as an Ardbeg 10 easily. A touch below your budget, but they do also do a more expensive cask strength version.
Away from Islay, how about an 18 year old Highland Park, still got that maritime edge to it, less peat, a bit of smoke, but from Orkney instead.
I am mainly into Islays/Islands, but if i fancy a change some of my personal favourite mainland drams are Glenfarclas 105, and some of Glenmorangie’s other tipples (Quinta Ruban, La Santa, etc) and i quite like a Dalmore aswell.