I feel like a large majority of the hate towards grampa Joe is just hating the poor for being poor. The man is 80, he retired when his job shut down 20 years prior (when he was 60). Why would you expect an 80 year old man to be actively working? He's 80! Let him be retired!
The bad guy isn't the old man who retired cuz he got laid off, it's the billionaire chocolate mogal who replaced his workforce with slave labor causing thousands to go without a job.
From my memory, he started out using the illegal immigrants. He didn't replace normal workers, although you can argue those jobs would have gone to the "right" workers.
He could sing and dance and jump out of bed when he won a free trip but he laid in bed and made his grandson take care of him before that. Joe was a dick.
I kinda want a Grandpa Joe movie starring David Spade. There's a bit of a physical resemblance these days, and there's so much weird stuff going on with Grandpa Joe in the movie that you could have a pretty full movie without Charlie, Wonka, or the chocolate factory.
A disability caused by work activity would be covered by worker's comp insurance.
Edit: in California all employees pay into state disability insurance. In the event they become disabled they could receive disability benefits from SDI. If someone were to claim to be disabled it would be disability fraud. Why are we even having this discussion and who cares?