I am so sorry for your loss. I have to agree with Kay, there is just no way to foresee accidents. I just lost my best friend yesterday and I feel as if I lost a part of myself. Death is the hardest part of life. It is something we all will experience and we all will have loved ones leave us. I just don't think it is possible to plan for the event of death. There is a story I heard a while back ( so I don't remember the details too well) but it goes something like this:
One day Buddha is approached by a frantic women, her son is dying and she begs him to save her son. So Buddha says I can save your son. First you must get me some spice from a household that has never experienced death. So this mother went through the whole town knocking on doors, asking has anyone ever died here? Yes..my wife, my husband, my mother, my father: she was told.
When she returned to the Buddha she realized that death happens to us all. It is not because you did anything wrong. In my opinion if your time is up, it is up. Kasashi had finished his mission here on earth. He brought you love and helped you love. Kakashi did what he was supposed to do and you helped him fulfill his mission.
How do we go on after we loose our best friend? We mourn, we feel the feelings, we talk about it and we take it one day at a time. There is no fix for this type of loss and there is no shame for feeling lost and lonely. Please respond and let me know how you are holding up.