What would you do, if your childhood best friend, who you dated and then broke your heart, wanted you back on his/her death bed?

DISCLAIMER!! This is purely hypothetical, as I cannot verify if this is true or not. And no this didn't happen to me or anyone I know, it's a story I saw.

The story goes that his childhood best friend, who essentially lived with him because her dad was abusive, started dating at the age of 17. They were both deeply in love. They went to college together. And then disaster struck. She developed leukemia. Her sister's weren't a match. Dad is dead at this point. Doesn't know where her mom is. He, the boyfriend, is the only match. So he happily donates his bone marrow to her. It was a painful procedure, but he was happy to do it because he loved her and intended to marry her. It's a slow road, but she gets better. Once she's fully better she sits him down cries, and tells him that she wants to just be his friend, he bawls his eyes out because he wanted to marry her. But he agrees because he doesn't want to lose her. Less than a week later she sees on her Instagram that she's out partying with some random guy.

At this point he reduces his contact with her to single word responses. For example when she told him she's now fully in remission he simply told her "cool". Most messages she sends get left on read.

Fast forward 6 years, she's had two divorces, and surprisingly no kids. She reaches out to him again, and it's worse this time, she's got a new cancer, and it's terminal, stage 4, some kind of small cell thing, and it's everywhere. She wants him to come back, stating she wants the one person who ever really loved her back.

The story ends with him just leaving her on read, and eventually blocking her.

I think I would have done the same, or if I were pissed off, I would have said "You left me for some random dude, got married, then divorced, when I dedicated my life to you, underwent dangerous surgery for you, loved you, saved your life, gave you my bone marrow, and then shat on me, and now you want me back? Not going to happen." and blocked her.
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What would you do in his situation?
What would you do, if your childhood best friend, who you dated and then broke your heart, wanted you back on his/her death bed?
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