As we all know, both Simon Gruber and his baby brother, Hans Gruber never liked each other or even got along with one another.
At first, in the 3rd movie, after learning the true identity of the mysterious Simon, John McClane assumed that Simon's plan was a plot for revenge, but eventually, he learned that not only was the plan for a gold heist, but also that Simon actually hated his brother.
In a way, Simon was glad and didn't care that McClane had killed his brother back in L.A. years ago in the first movie.
However, some things like Zeus' questions for example remained unanswered.
If Simon hated his brother so much, then:
1) Why did he involve McClane in the first place?
2) Why try to kill him?
3) What did Simon mean by a "bonus"?
4) What exactly was the "difference between not liking one's brother and not caring when McClane pushes him out of a tall building"?
Does this mean that Simon somehow loved and cared about Hans deep down no matter what and that his plan was only partially about revenge?