I have a different take on the subject than most of the responders. O.k. no one will know at what point you two became friends unless you tell them. In other words you could have been friends since childhood, or friends prior to your becoming a nurse... no one will know unless you tell them. We can't help who we become close to or who we find ourselves in need of their friendship. We are nurses with a license but before that we are human. I don't think this is unethical at all. Keep in mind nurses have gone as far as having intimate relationships with coworkers and patients, and yes even marry them, and guess what they still have their license. Now that's my take on it. I wish you well.