As a road warrior myself, I recommend a Briggs and Riley carry-on spinner. You quickly learn to live out of a carry-on only, so that you can get to the airport later (since you don't have to check luggage) and get out of it faster when you land. Briggs and Riley are expensive - you might have sticker shock when you first look at them - but they are fabulous bags with a fabulous warranty. I still use bags I bought 30 years ago - they have seen the world and are still going strong.
Here's my favorite bag of theirs for business travel:
https://www.briggs-riley.com/shop/c...domestic-carry-on-expandable-spinner-u122cxsp. It is professional looking, the fabric takes a nasty beating without missing a step and it lasts forever. My 30 years old bags are basically this style, although they've made a few updates to some of the internal hardware, etc. All of mine are in the olive color - while it shows dirt more than black, I feel like it's got just a tiny dash more style than the same old black everyone else has. The dirt can be scrubbed out most of the time, and when it can't then I just look at it as a war wound that I am proud of
I also really like
https://www.briggs-riley.com/shop/collections/baseline/baseline-commuter-expandable-spinner-u119cxsp - this one is a slightly smaller bag that will fit into overheads when other's won't. When I am travelling really light for just 2 or 3 days, this is the bag I reach for.
But if he's going to do any international travel, be sure to get one that is labeled "international carry on". The max dimensions are slightly different from the generally accepted domestic carry on size, and some of the international airlines can be really picky about making sure you match the size.