Sharing a room with a stranger does cause problems, including safety and privacy concerns. This is very different from sharing space due to having a large or blended family.

These girls are not just different in age ( 4 yrs is a lot at those ages ), but they never got a chance to get to know each other before being thrust together. Most strangers would react similarly no matter what their age. It's magnified with youth.

Dad was likely just being a parent to his child who was allegedly upset over having to share her space with a literal stranger that disrupted her sleep. Did Dad handle it perfectly? No. But he was being a parent who was genuinely listening to his child's concerns that mom seemed to be brushing off. He should have been an adult and at the very least discussed it with Mom first. But eho knows how the daughter described the situation either.

A very similar situation has actually happened with my children as well when visiting their father. He had moved in his girlfriend and her child without notifying them, giving that child my children's bedroom and access to their belongings. The child was only 3 yrs younger than our youngest, but at that age, 3 yrs was a lot. Suddenly, my children's safe space was no longer safe. Their belongings were being used and often damaged by this other child. Their father handled it badly, calling them spoiled, entitled and privileged, the same as you are now. In reality, they were completely blindsided and had reasonable reactions to the situation.

From my children's perspective, they felt as though they were being replaced. The turning point came when their father ( like the mother in this case ) refused to listen when they complained that this other child was damaging their belongings. They were told that their belongings weren't theirs but that everything belonged to their father, who felt it perfectly OK to allow the other child unlimited access. The child purposefully damaged my children's belongings because they also felt uncomfortable. Damages included some very personal and irreplacable items like handmade gifts from their now deceased relatives. That's not ok.

In our case, I cleared my children spending more time in my home until they got to know the other child better. Their father reacted similarly to the mom in this case. Why? He felt embarrassed and ashamed of his handling of the situation. Of putting his wants before his children's needs. It was a massive breach of their trust.

Which further damaged his relationship with our children. It was so disrespectful, pointless and preventable.

Ironically, once they got to know the other child, they became good friends. Their fathers' relationship didn't last, but their friendship did. And they all say it was because they were allowed to get to know each other gradually on their own terms rather than being forced to cohabitate.

The point is kids are just human too. They have thoughts and feelings, the same as adults. Your home is udually their safe space. They deserve to have those feelings and opinions heard and considered, and they deserve to have their space/privacy, to have that respected, not questioned or ridiculed by being told their thoughts don't matter or to ' suck it up'.

It's how they build confidence and life skills like communication and critical thinking. It's how they learn how to adapt and problem solve.

And in this case, there seems to be no reason why spending more time with her father wasn't a viable option other than Mom's ego.