My cousin 35M is creating a monster in daughter 12F

r/

I have to get this off my chest.. mind you I’m 28M married with no kids, so I tell me if I’m wrong here.

My cousin, who I’m pretty close with, has two little daughters.

We hangout a lot, but the relationship dynamic I’ve observed is very odd.

He refuses to leave the kids alone with anyone, so him and his wife get no date time (which she complains about)

The weird part is the relationship he has with the oldest daughter, he’s constantly holding her hand, complimenting her and giving her anything she wants.

He basically completely ignores his wife and other daughter, even making rude comments towards them like “I will take her to taco bell for our anniversary” and “don’t sit there, I want to sit next to my princess” (referring to oldest)

This has SHOCKINGLY turned the oldest into a complete brat.. she’s constantly complaining, making rude comments towards her mom, sister and even myself.

Mind you, I know she’s on her best behavior when we are around because past incidents.

He’s making a monster, I wish I could tell him and ask why he’s doing this, but it’s none of my business, which is why I’m writing it here.

So, how does this end? Has anyone seen this before? Why would he do this?

I’m genuinely confused/curious!

TL;DR – my cousin is creating a monster in oldest daughter by ignoring wife and younger daughter obsessing over her in borderline creepy way.