So many posting about guilt. I get it.
After some years I came to understand my brother made a bad choice in a desperate moment. His pain and exhaustion were just too much. He shared himself with us as long as he could.
Several years later, a therapist asked what I thought my brother wanted for me. Without thinking about it, these words came out of my mouth, “Peace. He wants me to be at peace.” It has been more than 30 years and I still believe that.
Look for a moment of goodness. Your posting to this site is an act of goodness. None of us want to be here, but your posting has/will help someone else. When we can generate goodness from this tragedy, healing begins. It is a long road, but you can find your new life.