Honestly, while it seems clear Catherine is not long for this world, I would not be surprised if Catherine felt it a just trade to give her life for her son’s. Also I could see Catherine’s deathbed wishes majorly impacting Henry’s decision to remarry.
Say Catherine lingers a bit on her deathbed I could see her saying a) she wants to name John after her brother/the saint and have Henry feel he has to honor that wish and b) urge Henry to remarry promptly to provide Mary and John a mother, perhaps even suggesting Isabella after hearing of her niece’s ticking clock.
Welp...that's a lot of foreshadowing that doesn't look good for Catherine. But who knows...maybe Isabella ends up in France! Or like, idk, Navarre. She'd probably hate that, but I'm guessing she'll be mad at any match that isn't the Emperor.
“The King will not see me,” said the Boleyn patriarch on that warm August morning, “His Majesty is still angry for what she has done and refuses to even grant me an audience, so I may explain myself. How can I make him see that it is not my fault? Had I known about her lewd intentions, I would have removed her from court immediately.”
George looked at his father. There is no question about whom he is speaking of so angrily, so full of resentment. Anne, their daughter and sister, who married the Holy Roman Emperor in secret. Anne, who stole a husband from the King’s daughter and heir, the Princess Mary. Anne, whom George missed very much.
“Give him some time,” said George’s mother, the Lady Elizabeth, “He will come around, I know it so. When his anger abates, he will forgive us.”
“I see not why we should worry about the King,” George murmured, sitting near the window. He looked outside, into the gardens of Hever Castle, their family home and wondered how long it would take before the King, known for his rash temper, would attempt to take it from them.
His father sighed, “George, we have talked about this… This is our home, our ancestral land. We are not going anywhere.”
George stood up and walked to where his father was seated, bending forward look him in the eye, “Annie is married to the Holy Roman Emperor. Charles of Austria, the most powerful man in all of the Christendom, is your son, my brother. Why are we still here?”
“Because I’m an Englishman,” Thomas Boleyn answered, “I will die an Englishman.” He waved his hand, as if the matter was not important, “And so will you.”
“No.” George shook his head, “I have my wits about me still. I can recognize that our family’s future lies outside of this island. It lies in the continent, at the imperial court, with Anne!” He sighed, splaying his arms wide, “The King will never forgive us. He will never forget what has happened and will always blame us for the Empress’ actions.”
“Be careful with your words, George,” said father, “And the King can change his mind. I have served him loyally for these thirteen years and such service cannot be forgotten easily. He will turn to us for services yet again.”
“You don’t know that,” George responded, insistent, “You can’t know that, but with the Emperor, who has your daughter by his side, we can rise higher than we could ever hope for with the King.”
His father looked at him and for a moment, just for a moment, George allowed himself to hope. He allowed himself to hope that he had convinced his father, that the man would soon tell their servants to pack their bags, prepare everything that was needed for a trip to the Empire. He allowed himself to hope right until his father opened his mouth.
“Do not speak of that whore,” he said, turning away, “She has forsaken her place in this family and we will not think of her.”
His mother gasped at the same time George took a step back, shocked, “How could you say that about your own daughter?”
“She is not my daughter!” his father bellowed, “No daughter of mine would have acted in such wanton ways.”
“Mary did,” said George, “Mary had two kings in her bed.”
“And her husband was made a Gentleman of the Privy chamber for it,” his father replied, “We are not leaving England. The matter is closed. We will not speak of it again.”
“But father…” George stepped forward.
“Have I made myself clear?” His father looked at him with an intense stare.