alexa play bulletproof

I’ve been playing mostly civilian, and have had the most fun looking around for all the cellar tools, or the car repair tools. In my search for said tools I always seem to find the SHOTGUN. I haven’t had a chance to really be aggressive in this game like F13, but I feel like even if I land (or think) i land all 4 shots, it doesn’t down him. I’m not sure if i’m maybe just missing it, but is there way to see how much damage he’s taken, and how much more he needs? Or a specific number of shots/melee strikes he can take before he gets downed?