Oh my Jim I am so sorry to hear this news. I sit here fighting tears though we've never really met.
I just don't know. You have so many wonderful photos of him already so it isn't like you have to "make up" for not having them.
If it were me, and it was not so long ago, I'd probably keep a camera around for the good moments, but wouldn't make any special attempts to get "the shot." I think I'd just let it happen.
I wish I could offer some sort of comfort.
Best,
Jim