as you prbably know, not being able to work because of illness is unfortunately not a reeason to get dla - it is dependant n how much help you need with peronal care/cooking and how much help you need getting around. In my experience, getting it has as much to do with how you fill the form in rather than how ill you actually are/ow much help you need.
im afraid i dont know the answer about fastracking the appeal, but if you can get a helth professional to support your claim you might have more luck. Or try cab. Or some local councils have a benefits service