I like seeing him having a mental breakdown like this, normally it's a really cliche and lame death, but this is a fitting jenga tower which we've seeing as an audience, piece by piece, get ready to fall. I like it, the misguided kindness of the family, the lack of attention to discourage him from pursuing the throne, the death of his mother and the growing distance from a king who doesn't know how to approach his son anymore, all of them building up to just a full on mental breakdown, no screaming, no weird anime eyes popping out while cursing the hero, just a mental breakdown that I can believe.
For all the horrible choices this manga has made, which have been many, I think that this cliche fall of the second trash Prince is decently well executed.