Working out the kinks ...

While I understand your argument, it brings up a few questions in my mind--If that employee is THAT fat, then was that part of the cause of the injury in the first place? And, also, can they absolutely not at all afford the weight loss surgery on their own? Because if they could afford the weight loss surgery on their own (and I'm not talking about have the money just lying around, because there are plenty of people who will scrimp and save for important surgeries) and their weight was a source of health issues (like, say, strain on their bones/joints/etc. that could lead to back injuries...), then the whole thing is their own fault to begin with.