If you believe that Bran Stark will make it to Winterfell and be reunited with his siblings, then you've probably already moved on to wondering how he will handle the information that his half-brother is really his cousin. Through his Three-Eyed Raven visions in the Season 6 finale, Bran discovered that Jon Snow's parents on Game Of Thrones aren't who Jon thinks they are. The Tower of Joy scene showed that Jon's mom is really Ned's sister Lyanna Stark and pretty much confirmed the fan theory that his dad is Rhaegar Targaryen. So will Bran tell Jon about his parents in Season 7? Knowing how important Jon Snow's heritage is to the Westeros, it would seem crazy for Bran not to.
After the Season 6 finale, Bran actor Isaac Hempstead Wright spoke with The Hollywood Reporter about the Tower of Joy revelation that Lyanna Stark is actually Jon Snow's mother. When asked if Bran fully comprehended the moment — since, to be fair, Bran didn't get the helpful transition of the baby's face morphing into grown Jon's face like viewers did — Wright said that Bran "can probably work it out" that Jon isn't his half-brother. And on how he would imagine Bran telling Jon, Wright said:
Yet, Wright's assessment seems to be underestimating Jon's open-mindedness when it comes to supernatural things. After all, Jon and Bran are part of a relatively small group of people who have seen the Night King with Jon fighting him, the White Walkers, and their wights back in Season 5's "Hardhome."
And there's that time that Jon died and was resurrected.
So I think he could handle Bran's visions and the revelations that come with them — even if he initially is reluctant to accept that Ned isn't his dad. Plus, even if he is disbelieving, that doesn't change the fact that Jon deserves to know the truth.
But one hiccup in Bran telling Jon that his mom is actually Ned's sister is that Bran may not know that Rhaegar Targaryen is Jon's father. Since the Season 6 finale didn't actually indicate the identity of Jon Snow's father, the actors involved have been careful not to confirm the R + L = J fan theory — with Wright telling THR in his interview "But we still are pretty clueless as to the father, I think." Harington echoed Wright's statement in a different THR interview when he said, "We know Lyanna Stark is his mother, but we don't know who his father is for sure yet."
Of course, if Jon isn't a Targaryen, what's the point of all the secrecy? So it feels safe to keep assuming that R + L = J theory is right since two-thirds of the equation has been proven — especially after an HBO infographic essentially confirmed it. Yet, Jon being Lyanna's son is kind of not as big of a deal as him being a Targaryen and without knowing the whole picture, Bran could cause some damage by only revealing Jon's mother. If Bran doesn't know who Jon's dad is, then one of Jon's younger "siblings" could claim Winterfell for themselves. Bran would probably decline since his role is to be the Three-Eyed Raven, which would put Sansa next in line. While that doesn't necessarily have to be a bad thing, Sansa has been working with Littlefinger and he should never be trusted.
The irony of Jon being replaced as King in the North, of course, would be that Jon has more of a claim to power than anyone else in all of Westeros if he is Rhaeger's son — he even has a better claim to the Iron Throne than Daenerys. Still, returning to the idea that Jon deserves the truth means that Bran should tell him no matter what the outcome is. And let's just hope that the identity of Jon Snow's dad is known before Jon inevitably meets Daenerys since the thought that Jon and his Aunt Daenerys could hook up without knowing their true relationship to one another is just too creepy a storyline — even for Game Of Thrones.