I saw a reddit post that Liam Jones was a reference to Fox's Peter Pan and the Pirates where Captain Hook has about the same background as Killian Jones in OUAT where he has an older brother and also used to serve the Royal Navy.
The difference lies in their relationship with their brothers. Captain Patch and Captain Hook have a Cain and Abel kind of relationship where Patch is trying to kill Hook for taking out his eye. Hook is angry at Patch for not giving him special treatment just because he's his brother, or rather a fair share of the booty. lol they really are a pirate family aren't there.
Whereas Liam cared for Killian since they were kids and was a role model for Killian to aspire to. Liam ensure Killian stayed in the straight and narrow due to the darkness they grew up with what with their father not only abandoning them but selling them to make up for his debt to the captain of the ship.
