You know what? This is a bit too real, but otherwise better than what I expected, which is the aunt being yandere.
The root of the problem here is the uncle though. His affairing aside, he...really doesn't have any sort of sensitivity. Can't read the mood, not smart enough to understand natural consequence, and doesn't have the empathy to realize what he's causing others to feel.
I don't blame papa for not trusting his own relatives.