Yes, it's natural.
I don't mean this harshly. Your H needed to tell you as soon as he became aware that he was having feelings about the anniversary of his sister's passing. You simply are not able to or responsible for reading each other's mind. At the same time, you could have mentioned your discomfort earlier, when it was a small issue.
It sounds like you're both at least thinking about ways to avoid this sort of blow-up in the future, and that's really good.
I suggest telling yourself something like, 'Raising an issue when it's small is an act of love. It opens communication and uncovers opportunities to give and receive love and support.'