So, one of my dad's friends is staying at my house for a little while. My dad said that it's because hes going through some stuff right now but that's about it. The thing that concerns me most is that he has a family and they're like a second family to me. His daughter is one of my best friends but shes been acting different, like not like herself...at all. I want to know what's going on on. I don't really care about her parents but she is one of my oldest friends. I think that it's possible that her parents might be getting a divorce, but I'm not positive. She hasn't talked to me in a while but I'm really worries because the last thing she talked to me about involved her running away.

Being concerned is normal, just don't pry too much.

i see have you just try'd too talk too you friend in private
give her a example like lets say even if her are going to divorce that dus not mean they dont love her anymore and tell her
wat her parents and family and her friends and you would feel like if she did walk away try too get her too realies how many people love and care for her try to make her think about her choise and get her too realies it her self.
and as much as i can agree with answer2 it feels it tells you to let her walk away i say not too pry too much that go,s on in her family but have a careful talk with her about her idea too walk away becose what she could use right now is her good friend .