My sincere condolances for your loss. This was a traumatic event. Everyone that has truly experienced one, deals with it in different ways, however, there are beneficial options.
Take care of your Father, comfort him in his time of pain and loss. Don't focus on the "why", just be there for eachother, the family as well.
If your inclined, seek the advice and comfort of clergy, they are a conduit to God. They have words of comfort, support, and have a good ear and shoulder to assist, there is support there.
Sounds like your from a small(er) town, most folks know everybody, or damn near. Go to the VFW, Moose Lodge, Elks, etc,.. and be around Veterans, and community folks that run a charity, whatever, I can almost assure you that many of them have lost loved ones, whether at home or on a battlefield. They have suffered traumatic loss and may have something to contribute.
Those that have been there can often help in healing without saying a word, or damn few.
Again, I am truly sorry for your loss. You are not going crazy, nothing may heal the images you have endured but there is support, prayers, and comfort to continue living.
Psalm 147:3
He heals the brokenhearted and binds up their wounds.
God Bless
tw