Snow tires have different tread patterns on them, which are designed to dig through the snow and channel the snow away so it doesn’t compact into the tread. Snow tires on drive pavement tend to be noisier than standard tires, and they have less of a footprint on the road, so they don’t handle as well, they also on dry pavement drop the fuel mileage due to extra drag (I seem to recall it was the tread pattern that did that).
AWD versions do weight more than fwd or rwd, that is true, which cuts down their MPG (ever notice when they advertise SUV’s gas mileage, it is for the 2 wd version?). That said, modern AWD units weigh less than the old part time 4WD vehicles, and because they have a viscuous coupling system that apportions power to the wheels, they operate a lot more efficiently, there is less driveline drag and losses compared to a 4 wd system, whether the 4WD was engaged. Cars like Ferrari, and cars Porsche and others put out, came with AWD, not for bad weather, but to improve the handling of some of their supercars, they had specific reasons to do so that had nothing to do with snow.
I am not going to disagree with the Car and Driver assesment, but I would argue that if you look at a typical driver, with typical driving skills, and AWD car might be more beneficial across a range of driving conditions, AWD can help in snow and slush but also can help in rain as well (and that is just my opinion). AWD is a weird beast, there is a kind of 2 edged sword with it, it can get you out of some mucky situations, like a parking lot that hasn’t been plowed or a muddy dirt road, and it can also give people enough confidence they don’t get nervous or scared about bad weather, and drive like the world is gonna end which leads to bad driving habits. On the other hand, as others have mentioned, you get the idiots, especially in the big SUV’s like the suburbans, explorers and the likes, who think AWD means “All Way-out Driving” (the $**%%(! adds that Jeep put out, showing the Cherokee on a snow filled road plowing along at a high speed was absolutely irresponsible, despite the fine print that says "professional driver on a closed course, don’t do this at home), among other things, the extra mass of those vehicles, which can be almost double a small AWD vehicle, also means that they are harder to steer out of a skid, take longer to stop, so when doing 70mph on a highway they are basically an unguided missile if they go out of control.
In terms of the OP’s post, if 30k is your upper end let’s say, you can get a lot of decent cars, both used and new. You can get a decent used volvo (which @doschicos is right, is built like a brick outhouse), you can get any number of the crossover/small SUV’s (CRV, Forester, Subaru Outback, Rav4, Mazda CX5/7, Hyundai Santa Fe, Ford Edge, the smaller jeeps (whose name escapes me), so you have a lot of choices. Unless they are planning to go truly off-road, any of that kind of vehicle should do well for them, after that it will be a matter of taste. Keep in mind things like fuel efficiency if they have to drive a long distance and use that in making the decision, too. I suspect given where she will be that all weather tires that come with the car will work fine, snow tires IMO are important in areas with heavy snowfalls more than just typical winter condition areas.