My only argument against your friend and anyone else who is angry or upset with this person who made a fucking fantasy wheelchair...
WHO WANTS TO BE THEMSELVES IN A MAKE BELIEVE GAME?
Do you know how to use magic? Then guess you can't play 99% of the content in the game! Can't swing a sword either? Well fuck, have fun being an NPC!
We better make the lich's dungeon wheel chair accessible or else we'll spend an hour every time we get to a stair case role playing how we get our party member down without burning a spell slot.
We could just have a IMAGINATION in a FANTASY WORLD, where you don't have to be constrained by the DEPRESSING bullshit of life, but noooooooooo... tell this person to kill themselves because they dreamt up a way to play a disabled person without having to deal with dark reality in a fairytale world... fuck. I work with the disabled and as mean as some of them can be none of them have told me to kill themselves because I wanted to do a nice thing.