At our hospital, the pts can opt out of being in the "Pt/Guest Services" computer-ie if someone calls, the operator has no record of that person being a pt. Same if they call the unit-we say "I have no information for you on anyone by that name"-which isn't technically a lie. I don't have any info for
you.
If they decide not to opt out, and someone calls, it's either "Yes, Ms. Jones is here, I'll transfer you to her room" or "No, we don't have a Ms. Jones on this floor, can I transfer you to the operator?" or something.
If you have no such policy, how about asking who's calling, having them hold, asking the Pt "Do you want me to transfer your aunt into your phone, or do you not want her aware you're here?" and then using one of the answers above based on what the pt wants. Otherwise, you really can't tell anyone over the phone that some one is a Pt, especially since you probably answer the phone identifying the unit as a postpartum. (At least that's what we learned in nsg. school and at other facilities I've oriented at)
The nurse you worked with violated HIPAA *unless* she spoke with the new mom who gave permission for her to inform her son.