The Young Sheldon season 6 finale secretly lays the groundwork for Mary's downfall and subsequent dark fate in The Big Bang Theory. CBS ends the family comedy's year with a massive capper that juggles several storylines. In the special one-hour finale, Young Sheldon season 6 tackles Sheldon's game-changing move to Germany for the summer and introduces a new complication for Meemaw's illegal gambling den, all while finally offering a pay-off to Mandy and Georgie's on again and off again romance. Amid everything, however, the Young Sheldon season 6 finale also subtly sets up Mary's less-than-ideal future in the prequel and beyond after she joins Sheldon for his study abroad.
Aside from Sheldon, Mary is the first member of the Cooper family ever introduced after she debuted in The Big Bang Theory season 1. Since then, she became a regular guest star in the series until it ended in 2019. Due to her consistent visits to Pasadena, viewers were able to learn more about her and her relationship with the rest of the family. Like her son, she usually shared stories regarding their time living in Texas, establishing her tumultuous relationship with George and preference for Sheldon over his siblings. However, if Mary had any signature trait in The Big Bang Theory, it was her religious leanings.
Admittedly, Young Sheldon is not known for preserving The Big Bang Theory's continuity. Over the years, it has created countless plot holes of varying importance. While many are inconsequential to the franchise's overall storytelling, some drastically change how Sheldon and his family are seen. Still, CBS maintains that both shows exist in the same reality. Given this, the viewers at least get an idea of what's next for the Coopers in Young Sheldon season 7. Per The Big Bang Theory canon, Mary returns to Medford to help the family after the tornado not only traumatizes Missy following her and George's near-death experience but also destroys Meemaw's house.
Now, it's difficult to say if Young Sheldon season 7 will spend time in Medford knowing that Sheldon is abroad. Despite the show moving away from the boy genius and increasing focus on the rest of the Coopers. The possibility that the upcoming year may be the last for the prequel further decreases the chances of this happening. Regardless of how CBS wants to tackle it, Mary's premature return to Medford could be the beginning of her downfall as a character, which has massive ramifications not just in Young Sheldon but also in The Big Bang Theory.
After years of spending her time serving the church, Mary is forced to leave the congregation when news of Mandy and Georgie's unexpected pregnancy came to light. Since Mary's departure from the church, she has become more agreeable to her family. Initially, she is distraught by the loss of her community, but it eventually becomes clear that many of her conflicts at home were rooted in her commitment to her religion. Mary accompanying Sheldon to Germany in the Young Sheldon season 6 finale would have likely not happened if she still has an existing connection to Pastor Jeff's church given her devotion to it.
Sheldon's relationship with Mary was established all the way back in The Big Bang Theory. While Mary tends to dismiss Georgie and antagonize Missy, she caters to the boy genius. This has been the subject of several episodes, and the root of Missy's contentious relationship with her mother. However, Mary's close relationship with Sheldon has its benefits. For starters, only the socially-inept Cooper kid can straightforwardly question Mary's devotion to her church in a way that she is forced to re-evaluate her values. If Mary comes back to Medford without Sheldon, she is vulnerable to re-establish her ties with her church.
Adding a level of complexity to the situation is Pastor Jeff's re-emergence. This starts when his niece, Tonya, befriends Missy. Subsequently, Young Sheldon season 6 finale further paves the way for him to re-establish his relationship with Sheldon's family after he accidentally discovers Meemaw's illegal gambling business. Connie's laundromat and video-store fronted make-shift casino has encountered several problems this year, but considering the Cooper neighbor's judgmental and self-righteous personality, this is arguably the biggest threat to it thus far. After discovering that Meemaw's house has been wiped out by the Medford tornado, however, Pastor Jeff promises not to expose her gambling den, essentially allowing it to continue operating.
Between this and Pastor Jeff's generous donation to Sheldon for his Germany trip, it isn't outside the realm of possibility that Mary mellows down on him. The fact that Mandy and Georgie are now also engaged to be married makes it easier for the rest of the congregation to welcome back the Cooper matriarch. Regardless of the specifics, this is Young Sheldon's perfect opportunity to reconnect Mary with her faith — something that was a key component of her character in The Big Bang Theory. Sooner or later, she will eventually re-establish her religious ties, but this is the most efficient way to do that.
Despite his motherly love for Sheldon, Mary came across as rude and highly judgmental in The Big Bang Theory, and she did it under the guise that she was only carrying out the teachings of Christianity. She criticized Penny for her romantic activities and made insulting comments to Raj because he was Indian and Howard because he was a Jew. In Young Sheldon, Mary's faith is also central to her character, although she isn't as devoted to it as she was in the main sitcom. So, the prequel has the responsibility to bridge that gap as part of its storytelling, considering that it now serves as an origins story for the whole Cooper family.
Mary's return to church has long been pre-determined. CBS cannot walk back on the way the character was portrayed in The Big Bang Theory. However, it could help if Young Sheldon provides additional context on how and why Mary is lured back to the church. Perhaps Pastor Jeff continues to pander to her and her family's needs and Mary feels obligated to reciprocate. It's also possible that she interprets Pastor Jeff's meddling as a sign for her to rekindle her faith. Whatever it is, it could help viewers understand Mary more and make her less despicable in The Big Bang Theory.
