It has to be tremendously difficult since you shared so closely with your friend. Similarly in our family a number of years ago, the husband of our eldest niece preceded your friend in much the same way. The trauma for the family and friends thereafter has lifelong repercussions.
Now his son, a small child when the event occurred, is a grown young man in love and making great strides in life. He and I do not discuss openly the hurt, as he lives for the now and that which comes. I am sure these coping mechanisms have been helpful for him in attaining adulthood and his recent college degree. It feels good to shower upon him my thrill for him at the strides he makes in his own path.
Hugs abound for you and those you yearn to help,
Mark56