Sounds as though you and your family have had a really tough time soHi,
I can only speak of my experience.
I lost my wife and my disabled daughter within weeks of each other, my wife totally unexpected, my daughter, her life was always going to be short but she was very much loved.
Aged around 11-12 she started not wanting to go out, it was her younger sister who cottoned on, time for Mum and I--a rethink as to her mobility needs and transport.
The issue really was the fuss of getting her in and out of her adapted, it started to stress her out, especially her wheelchair, she wanted out quick, with her sibling or friends.
To that end we purchased Peugeot Bipper, a car, van based, diesel with rear sliding doors, auto, t
Found a Norwegian company as I recall, who had rethought the design of wheelchairs and what made them heavy, what we purchased was an extremely strong, lightweight WC, hell it was light and slingable, daughter loved it, we all did to, so much easier.

I've had a quick Google but couldn't find the Norwegian wheelchair maker. I'm looking for an ultra ultralight wheelchair, I'd be grateful for the name if you come across it again. Thanks