Yes! This Lex Luthor is totally different from the one we all know and intensely 'dislike'. So, the tumor is not the complete reason for him accepting her behavior. Aykira is not going to allow him to bully her as we have seen from previous parts in the story.
Lex has done some bad things to a number of good people. You cannot rain that kind of havoc without expecting a little payback, which is just what this tumor is. He will suffer for his arrogance. I mean, how long does he have left?
The first writing on his reaction was a little tame, but my beta reader suggested Lex’s reaction would be more ‘hands-on’? But Lex’s most important emotional component (in this fic) is self-control. So he will allow rage, as long as it is controlled.
Why indeed. The lady has her reasons…