beta
The sister GAVE her permission so that her husband can have her brother. And they didn't date immediately, they stayed together in the same household for YEARS so that's definitely enough to move on and like someone else. The brother still feels guilty about it which is UNDERSTANDABLE but her sister gave them permission before she died so it's literally okay bruh. Yuki only decided to date his brother in law when he heard that the sister ALLOWED them to. And this isn't cheating, the spouse is dead anywat.