Single speed or fix gear. Mafac brakes, aluminum rims. Big enough tires and strong enough rims for whatever pothole he might encounter. Room for studded tires. I did this for years. 5 New England and Ann Arbor winters with no car. Commutes year round; 3 to 12 miles.
Mafac (or Paul) brakes because they are dead simple, powerful, reliable and will always work after a crash. (Winter ice - it happens.) No hydraulic lines to get snagged. No need to visit the bike shop to get them to work.) The Mafacs also have a wonderful "sponge" to the action that is both very predictable on ice and the like and works well on trashed rims which is a common state come March. That they are big enough to reach just about anything is a nice plus. Quite fender friendly.
Bikes that work really well as winter riders are the many Japanese sport bikes of the early to mid '80s, many of which came with 27" wheels. Put on 700c. Now room for those big tires, studs and fenders. Mafac RACERs will reach.
This bike wants horizontal road dropouts. (The rear opening track ends work but can be a nuisance when it comes time to change a flat and I promise, that will be in the dark, below freezing and maybe with precipitation.) Stay away from vertical dropouts. Yes, you can use a tensioner, but like rear derailleurs, after that first right side spill (remember? ice.) That tensioner may well be destroyed, perhaps with the chain bent also. Fix gear/single speed bikes can handle just about anything winter can offer and have zero issues save the chain rusting from salt. And here again that single cog in back and no tensioner means despite salt, rust and even a few solidly frozen links, the bike still rides just fine. Just slide the wheel forward to get the needed slack back. (I used to set three frozen links as the limit. Allowing the three extended bike overhaul times a lot.
It's pretty late to be starting to set this up for this winter. Last summer would have been far better. And fix gear for a novice should be started no later than late spring so when the going gets iffy, the correct reflexes are there. (Once this is learned, fix gears are wonderful in ice and snow. Like driving a manual transmission BITD instead of an automatic.)