For what i remember on the history, the king died too. When athy died and was the happy ending with the girl and her not brother, the king died and the not brother became the next king or something like this. But I think she still doesn't know that. Also I think his problem is the heroine (the happy girl) because I feel she is like a poison that serves a cure to his pain but actually is killing him.
@FeyFelyne
Athy and Lucas are pretty much the same. Adults stuck in a child's body. Didn't you pay attention to the previous chapter? This is Athy's 3rd life, this is her getting a 2nd chance on her first life.