Why We Sleep by Matt Walker goes into a similar topic. Paraphrased in hacker language by me, the gist is that the brain’s “cache” holds memories alongside the emotions. Whereas the “hard disk” part of the brain doesn’t hold on to emotions. The process of moving stuff from “cache” to “hard disk” happens during the dreaming/REM phase. Which is inhibited if you’re

1. Having nightmares that wake you up 2. Using sleeping pills 3. Using Alcohol to sleep

I’ve found that dreaming about the trauma/loss can soften the emotions over time