I went to boarding school in the country, so there's no real differentiation between family and friends. I went there from when I was 8 until I was 17 - it was insane. If you earn my friendship, you are my family, and I'll do anything for you.

The quote means that since the person went to boarding school in a rural area, they didn’t have a clear distinction between friends and family. They went there from a young age until they were almost an adult, and during that time they made deep connections with the other people there. If you become this person’s friend, then it’s almost like becoming part of their family, and they will do anything for you.