This is a documentary on Clive Wearing who suffers from both Retrograde Amensia (unable to recall the past) and Anterograde Amnesia (30-second, short-term memory).

About Clive Wearing (from a different video essay from YouTuber, VSauce2, about "musicality" that I previously posted):

"...One of Clive's only portal back to his life is Deborah. To him, her visits to the facility where he lives are a miracle - resulting in sobbing and clinging to her presence. But within minutes of her departure, he leaves messages for her saying:

'Please come and see me, darling. It's been ages since I've seen you. Please fly here at the speed of light.'

She would have had to travel at the speed of light to get there before Clive forgot that he needed to see her...."

The documentary is 48 minutes long.

EDIT: Just accept the small bit where Deborah "finds God". The comfort that offers is too strong sometimes - especially for those who are suffering. I totally forgot that video had that.