The search for Henry Winchester in Supernatural is a driving force for his son, John — but how can Henry appear in The Winchesters? Gil McKinney has been confirmed to reprise his Supernatural role in The Winchesters episode 7 (via TVLine), though the exact details regarding his return have yet to be revealed. Looking at the canon of both Supernatural and The Winchesters, there are several ways that Henry can make his return to the prequel series — and as John and Mary's search for their fathers leads them into war against the Akrida, Henry's guidance is very much needed.
After receiving a mysterious letter from his father written before the man's disappearance, John is thrust into a world of secret societies and demon hunting — just as John would inevitably lead his own sons into the world of hunting in Supernatural season 1 when he goes missing himself. Coming from a long line of Men of Letters, Henry supposedly lost his life during the 1958 massacre of the secret society. However, things like time travel, a shift in the Supernatural timeline, or flashback scenes could allow Henry Winchester to make an appearance in The Winchesters.
Henry's Appearance In The Winchesters Could Mean More Time Travel
Henry reappearing wouldn't be the first time Supernatural used time travel — it wouldn't even be the first time Henry Winchester himself traveled through time. In Supernatural season 8, episode 8, "As Time Goes By," Henry uses a spell to travel through time to 2013 after escaping the massacre against the Men of Letters, where he meets his grandsons, Sam and Dean. It is there that Henry actually meets his end and not in the massacre, as was believed. When he discovered how his son's life played out after his disappearance, he was insistent on returning to his own time to return to his son and right his wrongs.
Though Sam and Dean are successful in stopping him from changing the past, The Winchesters could present an alternate timeline where Henry is successful in returning to 1958 alive and reuniting with John, altering the Supernatural timeline. Henry clearly possesses the power to travel through time at his whim — and if the necessary information can be found inside the Men of Letters Clubhouse, it's possible that the Monster Club themselves could travel through time to find Henry instead. As John is so fervently fighting to find his father, it wouldn't be outside the realm of possibility for him to use this kind of magic to his advantage.
The Winchesters Could Feature John's Father In Flashbacks
Of course, McKinney's return doesn't necessarily mean Henry Winchester is alive, or that The Winchesters is bringing a massive change in canon. It's possible that Henry's appearance will simply be a flashback scene, perhaps detailing the fight against the Akrida, a previous case the Men of Letters had tackled, or the 1958 massacre itself. Henry has previously appeared in The Winchesters in episode 1, "Pilot," in a photograph with his family; while his appearance in episode 7 is likely to be more substantial, it could be in the same vein as John gets another glimpse into the past.
While it would be disappointing for The Winchesters show to miss an emotional reunion between father and son, a flashback scene could be representative of the Monster Club learning valuable information before their fight against the Akrida. The Men of Letters are the ones who have historically held back the Akrida, so anything that could be learned from them would be monumental in the upcoming battle. Even if Henry doesn't appear in the present-day Winchesters timeline, he could still hold a heavy influence on the way its events - and the events beyond it - unfold.
Would Supernatural Canon Let John & Henry Meet?
As Supernatural canon stands, John and Henry Winchester never reunited after Henry disappeared in 1958. While John would eventually learn of his father's true fate from his sons after his own resurrection, the two never again come face-to-face in Supernatural. However, if the series takes the alternate timeline in "As Time Goes By" where Henry returns to the past, it would be a change in Supernatural show canon supported by the possibilities presented in the series. The existence of The Winchesters itself already contests Supernatural canon, so this alternate timeline would both explain the discrepancies in canon and allow father and son to reunite once again.
The magical elements of Supernatural and The Winchesters gives the prequel series multiple avenues for John and Henry's future. Time travel could bring either John or Henry to each other's current realities, opening a door of possibilities in the future fight against the Akrida. If Supernatural's Henry makes the choice to travel back in time to find his son from his trip to 2013, it could have a lasting impact that changes Supernatural canon in its entirety. With so many options, there's no telling just how Henry will make his appearance in The Winchesters episode 7.