No, princess, don't call him "friend". Call him "husband". That goes the other way around as well, of course, but she did it first.
Seriously, though, I'm glad she did decide to contact him like this, regardless of if she intends to rely on him. If she's in some kind of trouble, she might have decided to avoid him to keep him, and his family, out of her troubles. I much more prefer how her desire to chat with him overpowered any such boring concerns. Even better if she asks for assistance, should she need any.
Edit: Like I said before, I'd also like the princess and the little sister to interact and get along. The little sister knowing martial arts ought to help with that.