My three sons-in-law enjoy getting a new book. I don't choose them but give them an Amazon gift certificate for whatever they would like. All three had recent birthdays and I received nice thank you notes from all of them. Good guys!!

Any of the Yeti products! My guys love their Yeti mugs.

A nice cashmere sweater?

The book/amazon thing was on my radar as he does like to read but was hoping for not a gift card. Still, not a bad suggestion:)

Will look into yeti , and cashmere sweater.

Elmer, your suggestion is fine but trust me, that's who we already asked and she has no ideas (other than pointing out his growing fine Scotch collection).

Is he into sports at all? Tickets to a game?

DH and I have enjoyed getting couples massages...perhaps something both your SIL and DD could enjoy together away from the kids?

Perhaps starting a very high quality power-tool set that you can add to over time? Makita brand is popular with some contractors I've used. It's possible his/their older tools may be holding a charge less successfully than previous years, and he/they may be ready to upgrade.

How about a set of nice whiskey sipping glasses, engraved,

There are beautiful editions of classic books at Folio Society.

Alexa/Echo Dot, if he doesn't already have one...? Kohls Link I just found a Black Friday Sale @ Kohles, $22!

Yes, I would ask your DD for suggestions, but if he likes Scotch, does he ever use a flask for travel? There are some really nice ones and my DH enjoys having some of different sizes on hand. And if they entertain, the nice sipping glasses are nice to have on hand.

I too enjoy my Yeti travel mug and there are some places where you can have them personalized. Be sure to get the lid that completely closes. They have improved them over the years.

Whiskey tumbler with lid....best idea ever! Whether it's a Yeti or a Klean Kantee...good ideas.

Does he have any hobbies or play any sports?

A dozen pairs of socks! (Not kidding.)

For the first several years that SIL and DD lived in their house, we bought him all sorts of power tools. He wanted to do some of the repairs to their very old house. Among the first projects was beautiful crown molding throughout the house. I wrapped an issue of the Handyman (Family Handyman?) magazine, found at our grocery store, and added a subscription too. He liked that magazine. As it happened, they did a feature on installing crown molding in the issue I bought him to put under the tree.

If he's getting to that stage in life where he can buy most anything he needs or wants for himself ... I like chisue's suggestion of a dozen socks. I'd make them identical work (or play) socks, so that he can toss them in the laundry and not worry about matching socks into pairs when they come out. It'll save whoever does the laundry time and trouble. If he enjoys cooking, what is the quality of the pots and pans he uses? Is he still using cheap-o starter pans? Maybe upgrade a saucepan or two to a high quality clad stainless steel. Maybe your DD could give you specific feedback on these specific ideas.

A book on cooking with using in some way and about the history of scotch. :-)

Monogrammed scotch glasses are a great idea Maddielee.