Official Rockstar Games clip, slowed down
Jason's friend
Cal Hampton
If it is on the internet, Cal believes it.
Official screenshots by Rockstar Games
Who they are
Cal is Jason's friend and, like him, orbits Brian Heder's business. Home is where he is happiest: listening in on Coast Guard comms with a few beers and half a dozen private tabs open.
Rockstar describes him as settled at the low tide of America and quite content there. For Cal the internet is not where people lie; it is where the truth finally gets told, and that is where the theories about birds flying in suspiciously perfect formation come from.
Paranoia is better with company. The trouble is that his friend Jason has bigger plans, and big plans are exactly what Cal has spent half his life avoiding.
What is known
Jason's friend and an associate of Brian Heder.
He listens in on Coast Guard communications from home.
“The psychopaths are in charge. Get used to it.”
Official artworkOfficial artwork by Rockstar Games — “Cal Hampton”
In the game
Cal floating in the pool on an inflatable. 
On the street at night, a bag over his shoulder.
Official screenshots by Rockstar Games