The Big Bang Theory already revealed the ultimate fate of Mary, the Cooper matriarch, who will eventually stop being fun and revert to her old, judgmental self. However, in Young Sheldon season 6, she goes through a crisis of faith and becomes more relaxed and loose, which allows for further exploration of her character. It is unclear why she will go back to being overly-devout, but the impending death of George could be a catalyst.
Mary's personal arc in Young Sheldon is interesting as it reveals a different side of her character and provides additional context for her actions in The Big Bang Theory.
