Yes - the guidelines say that time may be considered when counseling or coordination of care dominates the encounter. Yes - The counseling can be with the patient and/or the family - but I believe the family counseling must still be done in the context of a patient encounter. For example, you spend some time evaluating the patient who is unconcious or somnolent, then spend some time discussing the prognosis or plan of care with the family in the next room. That time may be counted. The provider isn't limited because the patient is unconscious and not able to participate in the counseling - it is medically necessary (for the patient's care) to have that discussion with the family.
I don't believe you are correct in your assumption that you can bill a child for an office visit for counseling the family without the patient even presenting to the office. Think of the implications -- you think Dr. Jones should bill the daughter even though the she wasn't there, and the encounter was just to counsel the mother? What if the parents are divorced, and the father gets the bill for the copay? The daughter says she never had an office visit that day... the father finds out that he is paying a bill for a service that was essentially done just for the mother. Since the claim went out under the daughter's name, that is potentially a false claim.
What would be the medical necessity for the encounter with the mother? Why wouldn't that just be a phone call?
I would be very careful about the advice you are giving.