This is a tragic accident that could have been prevented. Alcohol over indulgence and cold weather do not mix. With impaired judgment people do stupid things. Here in Alaska there are people who die every winter due to alcohol related stupidity. It really is a sad commentary.
I know I did a lot of cold weather camping. I enjoy the cold weather a lot more than the warm or hot weather. I have gone out of my way to make sure the heaters I use are very safe and do not produce carbon monoxide in a place where people sleep. It is always sad to hear about those in the outdoors not taking to proper care to make sure they are safe from harm.