I don't have any experience with boarding schools, but I wouldn't send my kid to one.
In my opinion it's like making your child an orphan. I know that may be overdramatic to some. I don't believe a child is emotionally or developmentally mature enough to go to one. Certainty not spiritually mature.
I'm not aware of any Christian boarding schools but that doesn't mean they aren't out there. That would be better, though it's still no guarantee that something tramatizing or abusive wouldn't happen.
I think we all have the right to be around people we love and who love us. Kids can be so cruel.. even worse now I would say. Imagine living with the people you work with. Um.. No thanks.
It's very unnatural. God doesn't mention doing this, although one could say Samuel was as close to this situation. However it wasn't full of kids. Because it's unnatural, kids will have strange feelings such as home sickness, missing their parents on a consistent basis similar to the loss of a parent quite honestly. They distract the kids with activities to help with this. That's something you do when going through a hard time.
On a personal level I couldn't handle camp as a kid, so boarding school would be over the top. Lol So I couldn't expect my kid to do it if I couldn't.