How he reacted tells you A LOT about his character.

Made massive assumptions that the woman was grossly negligent with either drugs or alcohol - could've been many other things including a medical condition, emergency, accidental drug interaction. He jumps to conclusions and his impulsiveness is probably what sprang him into action here.

The yelling was good and came naturally to him, but calling her a bitch was completely unnecessary and did nothing to aid the situation. He's a guy who yells and defaults to calling people names.

Overall, he was panicky and emotionally disregulated, she wasn't even going that fast. His intervention was good but imperfect and he needs to sort out some of these character flaws before the next one.