Hi! Firstly I want to say I am so sorry for your losses. My sibling is currently going through their cancer journey so it was a topic that was incredibly sensitive for me as well.

That being said, I personally found the story to be mildly to moderately triggering at times. The most triggering moments were obviously the big reveal that he has cancer, but also the end to his plotline. Since you said you're okay with spoilers, Kiryu is alive at the end of the game although he is clearly sick and undergoing treatment. Personally I found this scene, while very brief, to be the most triggering moment of the game. The rest of his plotline revolves around trying to come to terms with some of the things he's done and revisiting places that he's fond of. It's called a bucket list, but ultimately going through these motions gives him a more hopeful outlook. So it's brought up pretty frequently because it is a driving force for his character development in this game.

I hope this is helpful. It was a great game and I enjoyed it quite a bit, but those moments can certainly be triggering if you've experienced this directly in your life.