Now to the specifics.
Like I said, I agree with him that Democrats are sympathetic to more lax standards for disability benefits. It is a major component of their base that they wouldn't risk pissing off, but at the same time I don't know if I think they are rigging the system strictly to win votes.
The article does show that there has been quite a steady rise in disability benefits for working age citizens. Also having to "prove you cannot function in a working place environment" means absolutely nothing when the standards for the words "prove" and "cannot" are ambiguous and can be exaggerated.