He is part of everyone who is telling the truth. And we are to assume he is an honest man trying to do the most responsible action. The questions are who is legally at fault and what are the most ethically responsible actions for him to take.
I’ve seen a few people claiming the bus driver would definitely be legally liable. But I’ve not seen any cites to that effect.
Given the facts are not debatable (e.g. say there is perfectly placed cop with their dashcam running with exactly the right angle to see everything described: pedestrian, bus and speeding car). And the video (and other evidence, such as damage to the bus) shows clearly the car would not have stopped in time, and was heading towards a pedestrian.
I get in practice this would almost certainly not happen (most especially as the physics of moving a bus in time once a collision becomes inevitable, seems dubious), but if it did where in the law (of your jurisdiction of choice) does it say the bus driver would be criminally liable for saving the pedestrian?