Jesus, that's rough mate and you have my sympathies.
On my end visual violence didn't bother me so much, things more psychological could do a number on me though. It absolutely does depend on the child and their experiences, and that can only be properly judged by a decent parent or guardian imo. I could watch the old super violent zombie and slasher movies etc and not break a sweat, the only really violent movie that I saw and kept me up as a kid was Robocop, largely due to the toxic waste scene. I think it was a believability thing in my mind at the time. The idea of ghosts freaked me out a fair bit too, seeing Sixth Sense in my mid teens at the cinema caused me a few sleepless nights for example, my mother was losing the plot at the time and would sleepwalk while shouting and screaming and I couldn't get that one kitchen scene out of my head.