I do not doubt he has some level of PTSD. A cop can go their entire career and never kill someone. Two thirds of the military never fired a shot during the war. Rittenhouse killed two criminals in less than 30 minutes. At his age that is a lot to carry around within himself. People want to make him a villain or hero for their own purposes. He needs to disconnect from the past to move on.
Honestly, I would recommend he go to a University in Poland. Friend went to medical school there because it was accredited and so much cheaper than the United States. Rittenhouse wants to be a nurse, go to Poland, get your BSN and then return to the USA (if he wants), pass the NCLEX and be a nurse. Maybe the anonymity he would have in Poland would make it easier to focus on his studies.
Sage advice.