Surprisingly the “Luke Has A Moment” deleted scene doesn’t make an appearance in the novelization. I wrote a rough draft of what it might look like below:
Luke nearly recoiled from the gap in his doorway. The girl’s determined gaze reminded him too much of a younger version of himself. Confident. Bold. Reckless. And most importantly, foolish.
He sat down next to a floor table, easing his descent with his mechanical hand, which whirred in protest. She would never truly understand why he had chosen to leave the fight. Neither would Leia.
Leia. While he had lost the man he had come to see as his best friend, she had lost her husband. He couldn’t imagine the pain she felt right now. The worst of it all was that he alone was to blame for Han’s death. Everything was. And even if the Resistance wasn’t able to see it, his return would only make their circumstances worse. He knew that for certain.
Tears pooled on the surface of the table as Luke Skywalker wept silently.
It does reveal that Luke blames himself for things a little early, but it doesn’t reveal the specifics of that so I’m willing to overlook it.
It can already be inferred in the Falcon scene that he’s sad about losing Han.
Absolutely. But this scene serves more of a purpose than that. Because it comes right after he denies Rey’s request to return to the fight, it means he is brought to tears over what he has done and what he thinks he has to do. It isn’t just about Han.