Jack’s understanding of family is a very complicated and skewed issue that stems from three factors. 

Firstly, what memories he has of his mother are vague and far between – and the initial bonding between himself and his mother was interrupted by the fact he was born at sea in the middle of a storm. The safest place for childbirth on a ship was the gundeck, but neither the mother nor the newborn could stay there for very long after the process itself. 

While short periods of separation are quite common, supplies and manpower being what it was, leaving a newborn alone as long as Jack was isn’t particularly typical. By the time he was retrieved, he was already quiet as his early wails had been drowned by the sea – this lead to a frustrating muteness in his infancy that made bonding and understanding his needs at any given time extremely difficult.  

Jack was left with his mother at Shipwreck Cove, and under her care he did come around and eventually develop a proper needs based relationship by the time he was a toddler. He was very active as a child, and was in fact well looked after by his mother – but things took a turn after she died, which lead in to the other two and more complicated factors. 

The most defining of which, naturally, being his father. Or rather, the utter lack of understanding surrounding the concept of having a father and the fact that the “man who might be father” had a habit of obfuscating pretty much everything from advice to the true nature of their relationship.   

After his mother died, Jack was taken in as the cabin boy to Captain Teague, and he was very young when this happened – no more than five or six. Captain Teague was never very fatherly in the traditional sense. He was overbearing, demanding, and in certain respects incredibly possessive ( which at times could translate as extremely protective though Jack didn’t have enough of a bond with the man to register it as such ) but by no means did Jack ever feel as though the man loved him, or cared for his well being the same way that Mom did.  

Teague never spoiled Jack and he certainly never played with him or did anything that might be described as loving, but he always made certain Jack was capable of existing at sea. He oversaw Jack’s education and ensured that Jack could serve as a beneficial member to the crew ( and therefore better excuse his existence ) Beyond this, Teague ultimately made sure Jack’s needs were always met, without being overtly clear about it. 

Jack never starved or went hungry – but he was never given special treatment on account of being Teague’s son. If he wanted something, he had to work for it like everyone else. A point was reached where Teague expected Jack to be able to fend for himself – and again without really explaining it – simply stopped providing certain amenities. It wasn’t long before Jack caught on and did took care of those things for himself just fine, but there was a slight miscommunication / neglectful period as a result of that.

Jack had a vague understanding that fathers were a necessary part of existing, but little notion as to why until he was a teenager. Due to this, he had vague notions that he had simply sprouted at some point, and been taken in by Mom, with whom Captain Teague was close. This, then, had lead to him being taken on, which all made sense by itself until one took into account the occasional accusations that would come Jack’s way about being ‘Teague’s’ in some manner or other. 

While eventually reaching the conclusion that Teague might be his father, Jack never received actual confirmation of this from the man himself, and by the time that he did it was far too late for it to have much emotional impact. In fact by the time Jack was certain the man was his father, he already had a foundational sense of belonging to Teague, but by no means did he feel like there was a familial something.

Jack saw the relationship he had with Teague as a matter of possession. He understood a pirate doing right by themselves and ensuring that their property was unharmed and returned to them, far more than he understood the idea that there might be some sort of special bond between himself and the Keeper of the Code. Because of this, he genuinely believed Grandmama to be a title rather than an expression of blood relation – our third and final note of complication. 

Grandmama was violent, powerful and downright abusive. She had little compunction about stabbing Jack, and Teague was in no position to stand against her actions considering having grown up under her thumb he genuinely saw nothing strange in her behaviour. Jack saw Grandmama as a genuine evil of Shipwreck, and something to be avoided at all costs. ( Later in his life she is one of the few people whom he consistently wishes death upon ) At no point though, did Jack think for a second that they were related until he came to understand the fact that Teague was, truly and properly, his biological father. The understanding did absolutely nothing to endear the woman to him, however.

In short, Jack has no real idea of what it means to be someone’s son, or to have a family in the sense commonly seen. Because he lacks this fundamental understanding, he has a habit of not getting why people want to return to their families, where familial loyalty comes from, or even why people might miss their parents or children. This comes across as crass and uncaring, but in general he just doesn’t get it and is attempting to better understand his own positions by interrogating those with other ones without looking as though he is interrogating them. It is also why he generally ignores pleas on accounts of wanting to get back to family, as he is quite certain it’s a passing fancy – rather like his occasional urges to reconcile with Teague, his broken sense of family makes him incapable of fully empathising with the idea of genuinely wanting to get back to them or be involved with them in any way.  

Special thanks to @thecodekeeper who is the one and only authority on Teague I acknowledge, as 80% of this was framed through our discussions over the past few months.