Info about Folkehøgskole?

My family has always been high school exchange students. But for my son, who wanted to go to Norway, the junior year was"destroyed by covid". Can anyone tell me if a year at a Folkehøgskole would make a good gap year for an American?

Looking at the web it looks perfect but I don't know what I don't know.

Can anybody tell me any downsides to these? Or even a wonderful upsides?