Lmao, you guys reading too much shitty manga.
Relatives who occasionally come to meet others who younger than them often used beautiful or handsome, just because it was said by someone older than them doesn't make them a creep.
My aunt used to call me or my little brother a handsome kid during a family visit, that doesn't make her a freaking pedo.
I often teased my youngest brother too whenever I saw him bringing home his friends doing school project and some of are girls are cute so I teased him asking which one is his girlfriend.