This is one of those instances where a situation works well enough in a comic, but not in the 'real world'. Sure Roomie didn't tell Lillian about WOC being in a wheelchair, but Lillian could have very much spotted it herself.
That, and when talking about a friend of yours, you don't necessarily have to specify a handicap of theirs. It can come up in a conversation, but it doesn't have to.
But I'm glad readers were happy with how WOC's character was written. At least in this moment, I remember a few readers being specially thankful for this sort of representation.
I still had a lot to learn when it came to drawing suitable wheelchairs accurately though :D
--> This is a rerun of the finished webcomic Go Get a Roomie! You can find these two strips in the old archive >here<!