Link doesn't work for me but a few years ago Qatar Airways broke my daughter's wheelchair returning from Doha. It was transported in the hold, obvious to all what it was and I can only assume they had thrown it around judging by the extent of the bent wheels. This creates obvious problems at the airport and getting home but after much complaining they remained adamant they wanted to collect it and fix it which would leave her without a wheelchair for up to 3 weeks. In the end, the NHS provided a new one.
After that, we bought a travel wheelchair that collapses into a large kitbag, too big for hand luggage but BA have been great on longhaul and we get the bag in the cabin on most flights.