Sorry to hear of this. It doesn’t sound like a very accommodating way to deal with any customer, yet alone a GGL member.
Hope you get it sorted.
Perhaps call back and try a different agent?
As an aside, I frequently hear of people on this forum saying that GGL (or even standard Gold) is an asset to have for when things go wrong. Is that lip service?
I have only ever faced one rebooking crisis during snow disruption and then the fact that we all had Gold status meant absolutely nothing.
Overall, sounds like a farce.
GGL service generally great and a lifesaver for disruptions. As you can see not all the agents are good however but if you call back you will get someone else who are going to be helpful.
when there was mass cancellations at Heathrow and the queue for ticketing were outside the building I still managed to call GGL and rebooked to a flight. So it does help.
It does sound like a farce I had issues like this when there was a strike and BA rebooked me onto Air France. I had to push it but they did at the end.
it is possible to get rebooked to almost any carrier even non one world one however agents tells you different stories time to time.
Good luck for the OP I’m sure BA will take them home either Qatar or Emirates. (Most likely Qatar)