Actually now that I think about it @Loutre, if the team wanted to make a reference to Pirates of the Caribbean: On Stranger Tides with Ariel-Barbossa friendship they actually got it the other way around.
The one who drinks the water with a mermaid tear gets all the years of the one who drinks water without it. So, in reality, Barbossa would just give Jack his years if it was like in that friendship?
Unless the team knows something more and it was actually meant to be the other way around in the movie. I DON´T KNOW!