A set of Stölzle Glencairn whisky glasses at $24.95.
How does he drink his scotch?
If with ice, go with a rocks glass and throw in a round ice maker.
If he drinks it neat or with a little water, go with the Glencarin glasses everyone is recommending. They are my go to. Another solid choice in this vein would be a copita nosing glass. They're basically a Glencairn on a stick.
Whatever you choose, Amazon or Waterford, a nice touch would be getting the glassware engraved.
I just got some from Amazon. Unless you want them from the tribe web store, you can get some any time.
https://www.amazon.com/gp/product/B003QX2JMA/ref=ppx_yo_dt_b_asin_title_o01__o00_s00?ie=UTF8&psc=1
Very happy with them.
I took some pictures of a couple of Glencairns I have around, one is a known genuine glass purchased in person from the Glen Garioch Distillery, the other is from a 4-pack on Amazon (note it was priced at ~$24 when I bought it). To me, they look and feel exactly the same. The etching is also the same as far as I can tell. The packaging for the Glen Garioch glasses is obviously different from a standard Glencairn, but the Amazon glasses came in a plain cardboard box with 4 individually boxed glasses in it.
Glencairn Whisky Glass Set of 4 https://www.amazon.com/dp/B003QX2JMA/ref=cm_sw_r_cp_api_i_EXhHFbT443K8X
These are legit. It has the proper etching on the bottom. Currently 4 for $30.