If the garage is freezing that is not such a good idea, just like leaving insulin in extreme heat in the summer is not good. In the house should be ok- Is there a fridge there? I live in Louisiana and some people during hurricanes will use small ice coolers that have cooling mechanism that can be plugged into a wall. I know some of them have done this for months at a time
If insulin becomes frozen do not use it, even after thawing. The freezing temperatures will break down/ damage the insulin and then it will not work well to lower your blood sugar. Throw frozen insulin out.
It is also important to note that vials and pens have different storage needs
Cold insulin can sting a little, so it is best to warm it up. Make sure your friend knows they can warm it up by holding it in their hands or letting it sit out at room temperature for awhile. Make sure they never warm it up in the microwave!