There are really good YouTube videos on end of life, & what happens when people are dying. I found these TED talks very helpful. Sadly, I found them after helping my Dad, & Sister at the end of life. I wish I would have seen them first.
This one in particular will help you, I think:

But all of these are really good:
TED Talks
Dr. Leslie Blackwell ~ Living, Dying, & the Problem with Hope https://youtu.be/KQEWc3LVfyc

Kathryn Mannix ~ What happens as we die? - https://youtu.be/v9f6twy70iM

Ken Hillman ~ We’re Doing Dying All Wrong - https://youtu.be/gQVC-8WEB7s

Robert Macauley ~ Dying Well - https://youtu.be/T5qKXKDLMco

Heartfelt best wishes to you. Take care of yourself.