Going to out myself a little, but here goes...
In 2005, exactly as the Carlisle Floods hit (which may be a little more well known, thanks to Storm Desmond and his siblings), my MIL lost her DM (and my DH his gran). A year earlier, almost to the day, she lost her DF.
DM went to her parents house with DH and I. She had her own home in the village, but she had spent the last 15 months caring for her parents in their home. Because of the floods, everywhere was pitch black; it was January and the main substation was flooded, so we had no power, no heating, nothing. The house was so very cold and eerie; DH's gran had literally passed away in the living room a day earlier. But MIL wanted to be in her parents' home - she wanted to sit and reminisce with photos by candlelight and chat through her memories.
There was nowhere for DH and I to sleep - the sofas had been moved to make way for the commode, hospital bed and suchlike, and there was only one single bed upstairs to sleep in. The only other bed was a double that DH's grandparents last slept in together and it just felt wrong.
So DH and I slept on the freezing floor, just to be close to MIL. You know what? It didn't kill us and I know to this day it brought comfort to both MIL and DH.
What I/we did was nothing special - it's just what families do.