[Geordie Travels]

Hi Anaïs,
May I ask, how does your client normally transfer out of their wheelchair to, say, a toilet seat or commode, or to their bed? If they are used to using a hoist, then many airlines have hoists available for boarding and deplaning.
My sincere advice would be to contact the airline and the airport well in advance. Explain the entire situation and emphasise that the customer is unable to transfer independently and that the PA traveling with him is unable to assist with lifting. This will alert them to the need for additional support.
I would then follow up with a call 48 hours before the flight, where you reconfirm the situation and the need. Then, I would instruct the passenger to arrive with PLENTY of time at the airport and make themselves known to airport assistance at the earliest opportunity. When doing so, confirm for a third time what the passenger can and can’t do, and triple-check that the assistance needed will be in place.
It would also be wise to let the client know about the toilet situation on a long-haul flight. Whilst airlines do have aisle chairs that can be used to take a fairly independent disabled person to the (very cramped) “accessible bathroom”, they do not (to my knowledge) offer this same hoist facility mid-flight. I would recommend taking a look at this article that I wrote for my website: https://theworldisaccessible.com/accessible-bathrooms-on-airplanes-what-are-my-options/, which takes you through some of the many different options and techniques for wheelchair users (some of which are not the most pleasant, sadly).
Hope this helps!