When Gabby's family lost contact with her, I seriously doubt that the last thing in their list of 'What's Happened to Gabby' was that she was "gone" in any sense. There are many, many other possibilities. So many that I shouldn't have to list them. Lost/broken phone, accident and hospitalized, lost, psychotic break, held hostage in any sense, etc, etc, etc.
But "gone" - whatever that means - and they were being blocked from all the people who could have given them more information.
If Brian's family didn't think he was responsible for any misdeeds against Gabby, then why on earth would they not be willing to share what their son had revealed? And who wouldn't ask, "What do you mean by gone?"
MOO