If you RP a healer and you say...
“I can fix your blindness!”
“You’re deaf? I’ll cure it!”
“Don’t worry, I can mend whatever made you mute.”
“Hold still, I’m currently in the process of removing that character trait that you like RPing.”
Are you a Light-wielder? The virtue of Respect dictates that you must only help those who welcome your help.
Do you get help from the spirits of the wilds? Who are you to interfere with the natural order unless the person’s life is otherwise in danger?
Channeling some chi? What you would deem a defect may instead be the source of their personal strength.
In short, ask permission. No, it doesn’t have to make sense to you. Ask permission anyway.