It's OK to reach out to those who need help as long as they want it. People just need to be able to make the decision themselves and although we want to help them, we cannot push the issue. We know the truth about CSA and how things work, but those who haven't opened this "can of worms" yet don't know what we know and its important to leave it to them to find out.
I hope you don't guilt yourself for his death. We all lead busy lives and its hard enough to take care of ourselves. Part of you probably wishes you could have "gotten to him" earlier. However, no one could have pushed us into our recovery. We did that ourselves. We may have had people pressure us at times, or maybe not. But, ultimately, it was us that made that decision and it is us that chose to take this path of recovery. The one's that helped me the most were the ones that helped when I asked and the ones that let me know they would be there if I needed it and followed up on their word. I think, you followed up all you could. You did exactly the right thing. You offered help and that's all you could do. Unfortunately, he didn't make the decision to take the road you did before his death. You tried my friend. In fact, you did help him. You telling him your story probably made him feel like he wasn't alone in his issues. For that, you can give yourself some credit.
Truth is the very reason we strive to live. It surrounds and resides within us. Accepting the truths we already know and seeking out those we do not is a direct path to inner balance and joy. For life is not a means to an end, but a journey. Life comes and goes but the truth will always live on.