Is a parent child dynamic in a marriage ever healthy?

[Kellington]

Realised a few years back that my dsis is something like a tradwife. If that is what works for her, great. Try to myob after years of worrying that her relationship was abusive. But still being around them is always uncomfortable and it just hit me it is because they actually have a parent child type relationship. The way they speak to each other, make decisions is like a role play or something and getting moreso over time. Sis and I in our early 40s and BIL is mid 50s. Is this ever healthy? Am I awful and judgy for always feeling like something is off?

Ok,so that’s your observation. Crucially what’s her take,does she feel infantilised? Is she happy
It really all depends what actually goes on,the behaviour and the power balance
Does she have agency?can she chose independently, does she have her own money

She clearly loves being infantilised, beams like a toddler when he baby talks at her. Pretends to be afraid of things that are ridiculous to be afraid of, etc. He controls all the money but they are reasonably well off so she has all she needs.

whats her opinion is she distressed?does she know how you feel,have you disclosed it

She admits that he can be / has been abusive, but they are in a good patch. Not sure if the good patch is because of or if she thinks it's because of this new dynamic. My question is more if this type of dynamic is ever healthy. Obviously it would need to be with a non abusive partner to be.

Child- parent relationship in adults is obviously a power imbalance and can be problematic,yes
Really depends how it play out if people,want to be assigned those roles and are happy to act the part
child-parent can develop via bullying or dominance as one adult vies to be the adult and consciously or unconsciously the other adult loses agency and is the child

depends if the baby waby talking etc is a cutesy couple thing or a toxic imbalance