Until all 3 of you die because you accidentally started an uncontrolled fire while you’re already in an emergency.
2 people and 2 space blankets have just as good odds as surviving the cold than 2 people and some candles. Without needing to worry about fire.
A candle is going to heat up the area around it and dissipate that heat. The blanket will simply keep that 350 btu that you produce every hour much closer to your body, and stop you from freezing to death.