I have a legit question, does it really even count as grooming when you didn't really raise them to become your lover but raise them like your child but they are the ones who caught feelings for you?
Its not grooming if lets say for this manga, the man raised her with pure intentions/like a daughter in which she catched feeling for him on her own.
HOWEVER, the issue of whether or not the man reciprocates these feelings from his DAUGHTER is... another thing entirely.