Hey there,
I had a china gosling do the same thing- flipping and couldn't walk steadly on its own. I found that every time I dunked its beak in water for a small drink it did way better and would stand and walk almost steadly for a while. Then, after a few hours, it would do the same again and I would give it another drink by sudmersing its beak in the waterer. It took 3 days of flipping and watering. All in all, it made it and is my absolute favorite gosling. I think it was dehydrated... but all of the handling to flip it back over and give it a tiny sip of water really made it imprint well. It does still definately seem a little, ok a lot, stunned but thats what makes it my favorite. I wish I had that experience last spring when one of my early bronze poults did EXACTLY the same thing in your video. He didn't make it either. I should have given him some tiny drinks of water I think.
gp