Or you might be perfectly fine otherwise. If this forum's purpose is to help disabled travelers fly, then I would expect exactly this sort of question to arise -- or in more general terms, to find out what one can expect from airlines in the way of assistance for people with genuine medical issues.

Now, you may be perfectly right that airlines will simply say "if you need it, pay full fare for it" but I thought I'd ask.

I know bereavement fares don't get you a fare that is cheaper than low-cost economy, but it's still cheaper than full-fare Y. So I thought maybe they'd do something similar for disabled passengers (e.g. maybe provide an "I" fare even when I is sold out, as long as J is still available).