How to jumpstart a car with a REALLY dead battery?

[Maengelito]

A few miles down the road I realized, couldn't I have just pulled the positive terminal off his battery, connected the jumper cables (with one to his now loose cable, not the positive terminal obviously), started his car (assuming it started), then with cables all still attached, reconnected his positive cable, and disconnected the jumper cables? That way, his car would have never been without a battery as he would be sharing ours, and well, I already exposed our car to his dead ass battery, so this doesn't sound any worse from our car's perspective. And if his ran 5 minutes ago with that dead battery in the way, I guess it should now.

I wouldn't see why that wouldn't work. If you were really worried, you could've removed your battery, connected it to his car to see if it would start and then reconnected it to yours. You could've also connected his battery in the meantime to your car to see if it would start just to see if thats what the issue is. That should atleast confirm or eliminate the battery as being the culprit for his car not starting.