Our dog passed away 2 days ago, does our other dog understand?

Hi there. Our black lab, Molleigh passed away extremely suddenly 2 days ago. Mom was home and I was at work. No warning, no unusual behavior just got sick, wasn't responsive and passed all in a 5 minutes span.

First off she passed at home, our other dog was around when it was happening. She smelled her, licked her, laid next to her. Does she understand what happened to the other dog? Dad took the dog that passed to get cremated. I'm extremely worried she's just....waiting for her to come home, she seems okay but I'm just not sure....

I....hate knowing that was the last time I saw her. I both want to know what happened to her but don't wanna know in case she suffered. I hate the idea that she suffered. She was only 10. I would tuck her in every night when my parents went to bed.