Hey Peter. Pain and grief can’t be compared. Maybe your brother had it worse. That doesn’t mean you’re not entitled to feel hurt by what you witnessed. You’ve seen the lowliest of human nature, and hell that hurts, no matter if someone was aiming at you or you were “only” taking pictures.
Allow yourself to feel the pain, and name it for what it is. Get your life back. Get your wife her husband back. Good luck.