That's an incredibly interesting take. Flipping the script, is it useful or ethical to find a way to help him monetize his purpose in life to his benefit?
Sure, but probably not in the form of a traditional job with an employer where he would likely endure mental trauma over mistakes being made at a job that he depends on for money.
The sad part that most people do not understand is that if he's on 'assisted living' and gets a job he may no longer be eligible for it ever again, even if it doesn't work out.
So the idea to push a job on him could actually be the death of him and what's worse: chances are good that he might even do it to his own detriment.
Edit: reduced unintended tone. ;)
When you strip away the notion, or often the facade, that jobs are not a form of enslavement then you might be asking yourself the question I'm asking: Why would you want to do that to him? It's not like he hasn't been able to find a purpose in life to keep himself happy. Or do you really know anything about him or what his needs are to suggest a 'job' would be of any help?