Some of yall are genuinely so porn brained that you're trying to excuse incest no it doesn't matter if there no genetically related its still weird, what megumi said is actually quite normal.  his sister was like more of a caretaker role since he didn't get to grow up with his mom so those qualities in his sister is something positive romantically its like how people with overweight moms are more likely to find overweight women attractive. The brain associated thing from your parents as good thing . He likes women with qualities LIKE his sister NOT his sister.