I'm very sorry about your dad and that your friend responded so coldly to your phone call :(

I've just come to the conclusion over the years that many, maybe most, friendships are situational. Break whatever common bond holds you together and with that glue gone, the friendship dissolves. I learned that lesson young due to being a "military child"...we'd move, and I'd write and write, and not get responses. Once I was gone I was forgotten. I have a very few friends now that are the type that I can go years without speaking to, but if we were to get together we'd pick right back up. Those are few and far between though.