-- These days, with the internet so available and unfortunately with people not always being who they profess to be, it's a rather common occurrence to look into backgrounds.
It may be said that this gentleman was - as a good friend - looking out for her.
I can understand that she feels her privacy was violated, but there really isn't any privacy anymore.
As long as the doctor had nothing to hide, his information is public property. Chances are the gentleman friend could have found it out in the 'yellow pages' if it was a few years ago.
The internet is today's 'yellow pages'.
Best thing to do? Make it clear that the gentleman friend did not ask his daughter to do this; the daughter did it on her own.
It might not be worthwhile to explain to the lady friend that no one dug up information that this doctor didn't want known. I doubt that was the point of her being upset. Her feelings of people looking into her business without being asked or given permission is what's got her angry.
Only a simple "I'm sorry. I won't do it again" and time will fix this.