I wasn't sure you'd read this post but knew if you did that it would probably cut close to the bone.
That image you have, I have similar of my mum who died very badly and I'll never be able to shake those images loose from my mind. I guess that's why I focus on the lives of those who depart rather than their deaths - I've seen some bad ones and I'd rather remember the good about that person.
I know it'll be difficult for you still, that may fade slightly over time but will never leave you.
Remembering him does gave me strength at time...no wonder, I can not be like him, but alwsys think of him whenever find myself in trouble....it was very fresh so not easily go away..neither I want to forget him as a person...I never seen such a close death before.
Death is often confronting and most never really see it enough to get used to it, as used to it as one may anyway.
Just take your time with it, remember who he was as a person and in your life and allow yourself the time to deal with it in whatever time it takes.