If he wants to buy good whisky and put ice in it that's entirely up to him - drink it any way you want. Me? I'll take it neat please. Add some water for some of the high proof cask strength stuff.
We regularly get out the 'unicorns' for a select group of friends like the Ardbeg 1977, a Talisker 25, St. Magdalene 19. Last Saturday was our Burns' Night Dinner and we had several bottles to sample. This time the favor was returned with this magnificent 1975 Glenmorangie which one of the guests brought along. Distilled in 1975, bottled in 2002 at 27 years old, and nurtured since then. To say it was like drinking velvet would be an understatement.
Same guy at Thanksgiving gave me this 1989 Bruichladdich. Cask strength at 58% ABV and heavily sherried it was an absolute gem. He claimed he didn't like it, which I can only imagine was due to the overpowering sherry influence. That said, he seemed to like it last Saturday but didn't want it returned when I offered.
We tried several bottles that night. In the background of the Glenmorangie photo is an Old Potrero. It's a 100% malted rye, cask strength, finished in port casks, and an absolute cracker. Not Scotch, but someone wanted to try it. The Macallan is the 2019 'Classic Cut' and also at cask strength. I think there was a lot of cask strength going on that night as we also had a CS Glendronach.