A little too late!

Diluc often left things too late. What if he realized Kaeya was always his brother during the fight but realized too late and killed Kaeya only to wake up from a dream. After having an eye opening experience Diluc tries to mend his relationship before its too late but not finding Kaeya where he should be makes him worry that it is too late

Diluc has a dream of actually killing Kaeya on that night and now is determined to make amends before its too late.