I agree....so would I. Sounds like he did a good job with what he had. As I mentioned before in another post, sometimes the life safety issue may outweigh the potential trouble someone may cause you later for it. Once again, I don't think we disagree here.
It is a matter of risk vs. gain. My point is that filling ones O2 kit with industrial grade oxygen is not necessary and adds an increased risk of introducing toxins into the already weakened system of the injured diver. Sure, it might be fine, but I would rather stack the odds further in my favor by using oxygen that has met the FDA requirements regarding filling and handling. You made a similar statement with regards to oxygen percentages. I will not fill my oxygen kit with anything less than medical grade oxygen. My life or that of my buddy are too important. The risk may be small, but its an unnecessary risk.
Once the bottle runs out, the balance of risk vs. gain changes, and just like the diver you mentioned I will take whatever I can get.