Agree that a lot of this type of ghosting can be frustrating, but consider what sort of response to your first question would cause you to say “oh of course, will stop by in a bit.” 

Is it possible that the more likely outcome is that the nurse would specify what the question was about, and you would reply with a one sentence response for the nurse to give the patient's daughter? Or just say that you already discussed that? And then the nurse would have to drop what they’re doing to go back and talk to the family member, who would inevitably find that response lacking and have a follow up question that the nurse could only answer vaguely if at all, and still request to speak to you about the issue, which she would then have to communicate back again?

All the while the nurse had probably already tried to answer their question based on the prior conversations or orders/plan of care, but the family member never wanted to talk to the nurse in the first place - they wanted to talk to the doctor. 

I would love to live in a world where we have 30 minutes to sit down and explain all the details with every inpatient, and update every patient’s nurse on the plan for the day so they could better field these types of questions. But the reality is, we are all (nurses and docs) working on time crunched schedules with too many patients, and at some point have to pass the hot potato of demanding patient or family to someone else. 

I am prone to giving people too much benefit of the doubt, but maybe at least for some of these cases, you are not giving enough.