I have a trigger warning: my experience with ptsd
Do want to cut someone out of your life because of your ptsd?
Yes I do, but I'm afraid to because of lack of closure
If you have mental issues you should seek professional help. This can help you work up the ability to cut out a friend you no longer want. If not, you'll continue in a toxic friendship because you are unable to work through your issues.
I feel fine but I need a third party to help me decide whether I should cut my friend out of my life.
That is a good idea. PTSD is serious so getting outside help is very important. They can help you make a good decision.