This is more life than sports but bear with me.
Losing class mates in your youth is just the worst. No one feels the unmuted pain quite like a teenager who has never experienced it. My (HS) graduating class was just bombarded with weird deaths from about 8th grade til around the end of college. A heart attack, suicide, cancer, murder, drowning, leukemia, car accident...it kind of ran the gamut. The first one that I knew well was really difficult to deal with. I dreamed about him constantly for weeks after it happened and would wake up screaming. After awhile we stopped wondering which one of us was next and got on with life, but out of around 140 people we lost 10% before our 5th reunion.
It sort of slowed down for awhile and then started up again in earnest, but while it's never easy to say goodbye to old friends it does help when they've had a chance to live life for awhile. Still, we never know what day will be our last or those of our loved ones so make those amends and tell each other you care while you can.