I'm sorry to hear about your friend. I'm afraid to many of us have lots friends this way or have had near misses ourselves. Years ago I lost someone who had pulled a car onto it's side to remove a transmission or something. Those were the days when people would just abandon cars in fields and you could just go out and pick them apart. As he was removing the trans for his 55 Chevy convertible the car he was working on came crashing down on him. They didn't find him for a couple of days and then it was just his feet sticking out from under the car. I've also always been leery of working under my cars, always used floor jack, two - four jack-stands, wheel chocks and wooden wheel ramps. Depending on what was being done. My condolences to your friend's family and friends.