In the Occult Book shop there is a bottle of eye drops located on the counter. Pick that up and "Use" the eye drops on each of the main (living) players. Each one will cry and talk about regrets. To complete faster, wait until you have control over Ray, Reyes, Dolores, and Ransome. Obviously, our ghost friend won't be able to use the eye drops and is not required to complete.
*edit* You need to have Franklin "despair" as well to complete the achievement. When I was playing through I did this just to see what would happen and didn't notice achievement implement. Thanks Dale Baldwin for pointing this out.