My heart goes out to you and your family. Someone I knew committed suicide many years ago, and it is very hard to deal with the loss. We want to kick ourselves wishing we could have done something to prevent it. For years I carried guilt because I am pretty sure I was the last person to speak with someone relatively new to my church. I hadn't seen her in a while and told her I'd catch up with her after the church service. Her demeanor changed abruptly and she flew out of the room. I tried to find where she went, but she disappeared into a crowded Narthex. Figured I'd find her afterwards not knowing what would eventually transpire.
As difficult as this loss is for you and your family, please know this wasn't your fault. Sure we can say to ourselves, 'what if I had done ____, this wouldn't have happened.' But we can't change the past. Sadly there will be many emotions to experience as you deal with this tragedy.
You might want to consider chronicling your emotions through your photography. Find some dark subjects to shoot that represent your pain. Then make yourself find something positive and uplifting to shoot even though you feel like crap. You see, it's in the process of looking for the positive (even though we aren't always able to find it right away) that helps to move us one step at a time towards healing. May you feel the love of God as well as the love from others as you walk this stretch of your journey.