Are you sure Luca is not reincarnated?
Well from the spoiler that I read, the aunt regretted her past action about letting him go (basically sold him to Vinterland) and decided to join the villain (Franz) so she could protect him. Like double agent ig?? Yet she still got killed in the mid of it..
And when the uncle dying (in the past life), he said to Luca that he protects him because of duty not familial-love.
That made Luca, before regressing the timeline, realized blood-related is much more important than anything. That's why he's not angry anymore to his aunt.
You!!! You little piece of shit!!!!