Agree, we have one of those too. Last Saturday we went to a party and it was bitterly cold; -20F. I put the battery pack in the car, but did not need it. However, it woul have come in handy if my battery had been down or worn. It’s cheap ($50) insurance.
Where I lived, in the middle of the Midwest, we might get -20 every year or two, at night. Once in a great while it would hit -30, and sometimes with lots of wind, with wind chill close to -100. People at work would be all over the place as to what they were going to do. A few drove home, parked their car, and went out in the morning to see what happened. Most started, but some didn’t and as OP pointed out they sure suffered out their fighting the cold and car.
Some said for what it costs, and the fact it’s only once every few years, I’ll go out and start it halfway through the night, and let it warm up good. All of them made it to work on time. It even worked for me some years ago when I had an old beater. After that, with a better car, perhaps it would have started anyway, but once every so many years, I was willing to do it, as unpleasant as it was to go out in the cold at 2 am.
But, clearly when it happens a lot, one must simply make that car so it will start all the time.
Talk with the locals and do as they do. Been here - done that goes a long way. In North Dakota we have Edmonton +++ winters. Too bad you can’t use tank heater. That would have been a quick solution. Sub-zero temps drag your battery big time and if you do lots of short trips, it will eventually get down to where you won’t be getting your important after work start. If this fits you, then do the noon start up on -10 days or even take a short drive. Yes, it retains some heat that helps your after-work start but more importantly you get to keep that battery up to max. 50/50 in the coolant.
I’ve lived in North Dakota where it gets -40F and colder, and you’ve gotten a lot of good advice. The best is Dag’s suggestion to get a portable jump starter that you can roll inside with you. Another is Doc’s suggestion to put a quilted blanket over the engine.
As everyone has stated, a plug in engine heater is a must. I had a lower radiator hose heater coil and it worked great. The coolant circulates by convection. Block heaters work the same way and just as well, but the lower hose heater is a much easier DIY installation.
These are both such bad ideas.
It won’t make a bit of difference in engine wear. The battery isn’t really the problem here. If he’s got a good alternator, the battery is relatively new, and he isn’t leaving his dome light on, he’ll have enough power to start. Sure, what you’re saying won’t hurt. But the reason for having heaters is so that you don’t ruin your seals or even crack your block or head or intake.
I’ve seen what can happen in just one interior Alaska winter (take his Edmonton winter, and subtract 10 or 15 degrees for most of it, also add a month or two). I was car shopping and looking at a Cutlass owned by a Chinese grad student. He’d never driven before coming to Alaska, never dealt with a car before. He had no idea, and no one was kind enough to tell him, he needed to plug the car in. What did I see when I popped the hood? A crank case and radiator both full of a swirling mixture of oil and coolant.
That is the kind of damage that can happen. It’ll probably happen more slowly for the OP. And it’s far more likely that the thing will just end up leaking oil like it’s its mission in life. But something bad will happen.
THAT is what the real concern here is.