My DB sent his children to a boarding school, despite SiL not working.
Now, i can see both sides, the children eventually settled and achieved great grades, doing really well, they had opportunities those in the state sector are unlikely to have.
But the parents missed out on so much, which comes with bringing up children, both the highs and the lows.
Both parents and children say they wished they'd gone as Day Students but that would have meant a "lower tier" private school, which at the time, didn't seem an option.
They missed out on growing up around their cousins too.
I loved bringing up my kids, i wouldn't have missed any of it, the idea of having kids and then allowing "house parents" to bring them up is horrifying for me... but we are all different.
Parents do what they think is the right thing at the time, i wouldn't judge anyone for their choices.