You're free to say whatever you want, but you should know if you give away a story's ending or share in casual conversation something about a character living across multiple sequels who is often in peril, then you force me to assume I've seen the iceberg's tip of your potential cruelty (or inconsiderateness).
Yes, you are free to spoiler. And I am free to hide all your future posts, unfollow you, or assume nefarious things about your intentions.
Updated to add: Rereading this I realize it comes across as pretty harsh. To clarify, I've never minded general talk about an author or a story. It's when people throw out crucial specifics, like so-and-so died, and they say it without warning-- that's what I'm talking about here.