As you say: XRotor 40A ESC, fully charged tattu Rline Hobbywing, insane big motors and durable props. His fingers have lost a bit of flesh in the process, but he is back in pretty good shape.
It happened last month, I am just mentioning it now as I wanted to see how this would end-up before mentioning it in a public forum. He was lucky the hospital was 400m away, and the surgeon did a great job. Could have been much worse though.