Yea, this sounds like a completely reasonable process to me. They should obviously update their system to accept the electronic submission of evidence, but the process itself is fine.
The demand that poor blind people acquire and submit records through an obscure technology, at their own personal expenses, on short deadline, is obviously absurd.
In particular, the requirement to re-prove basic facts suggests a fundamentally hostile design - you could just ask them to send a simple email asserting that yes, they are still disabled; or have them check a box and return a form.
Is there's truly an epidemic of people staying on welfare after their lifelong disability was cured?