I don't think you need to do anything in particular. I will say that, in my direct experience, letting go was very helpful. I found myself regularly seduced by the promise that knowledge would release me. I could only relax if I knew more. If I understood then I could position myself appropriately. I needed to learn the rhythm before I could participate in the dance. All of this was untrue and kept me in a sort of stasis. I felt more like an addict reaching for just one more conceptual framework that would neatly resolve everything. None of them ever did and I do not believe any of them ever can because this is not a problem to be solved. The intellect, for the most part, is the wrong tool for something like this. This is an emotional wounding and we can't think our way into healing.
Is it necessary to witness these things? I can imagine situations which require this but if there is any way for you to NOT read these things then it seems like it is in your best interest to not read these things, at least for the moment.
These questions, to me, imply a certain singular ground truth that can be extracted, if only you can work hard enough to perform the necessary grunt work to get it. What if the words he wrote are absolutely meaningless? What if they say more about his own hopes, and fears than anything externally legible? What if by trying to interpret them you are effectively trying to taste the color green with your elbow? (thanks Ursa)
My only input is that whatever questions you have can only be answered with time. Right now you are best served by redirecting your energy away from the rubble and onto yourself. What do you need? How can you be comforted? Are there friends that can console you? Are you heating enough? Are you eating healthily? Are you going for walks? Spending time in nature?
It's just this, for a while.