I had the misfortune or pleasure of practicing Family Law for 10+ years and I was shocked by the lawsuit and in fact thought it would be ruled frivolous and the parents awarded their fees against the daughter, attorney who filed it and Friend's dad who is paying for the suit, but I thought the Judge handled it well.
First, the daughter is 18, if she is within her ADULT rights to move out, she is on her own. It amazes me the audacity to say I am old enough to decide where I live, but you have to pay for my school and college.
Second, even if she was a minor, the Judge handled that well, by the following slippery slope argument, where does it stop - school, an xbox, a TV, a different dinner, not enough things to eat. They are the parents and as long as there is no neglect or abuse, it is their decision how to proceed with their daughter.
Third, on a side note, I would if it was my kid, brat spoiled bitch or not, continue to pay for her high school, but after that later days kiddo.
I feel bad for all involved and think the friend's Dad is an asshole for organizing this whole ordeal.