Depending on what phone your friend is using, and the OS version, he may be able to retrieve the notification history (not all phones allow this, but some do). I really doubt this has anything to do with it, but it you’re capable of accessing the history log you may be able to see something or other.
I also think it's a different source, I really don't agreed with OP post of this notification, something else is attached, you know how Newbies act, I guess he must have done something else