Wiki visits with family members

[solocoder]

I know that in certain cases we can bill for visits with a patient's family members without the patient present, but... when a patient has already discussed surgery with the doc, but wants to come back with their spouse, or other relative, to have the doctor explain it to them too, would this be considered medically necessary? I was under the impression that this is only done if the patient is a child, or incapacitated in some way. We're talking about fully functioning adults here, and the "decision for surgery" has already been made.
Does anyone know of some reference or guidance on this?