My props to your dad and his buddies.
Camping for long stretches sucks, even when it's not cold, but winter is much worse. I've done field work during the winter and you never really get warm, regardless of gear. Even a fire only warms whatever side you have facing it. The other side is still cold, especially if it's windy.
The toll on your body adds up quickly. Without proper googles/glasses, eyelashes freeze shut in the wind. Fingers and toes get cold and numb and stay that way, making them clumsy and stiff. Every ache and pain becomes magnified due to the cold. There are a lot of middle aged+ Russian troops in horrid physical condition. They are going to be feeling every one of those aches turned to 11.
Every part of it is miserable, even with good gear, which none of the RU troops have. When General Winter starts fucking with their minds and bodies, Russians will be surrendering en masse just to get warm again.