They would be in their late 30's or early 40's.

Anniversaries are painful.
The loss is fresh again and grieving people are confronted with the sad changes that have come into their lives. They wonder how different life would have been had the loss not happened.
April 20, 2024 marks the 25th anniversary of the Columbine mass shooting. I remember where I was standing by the front door when my son said from the car, "There is an active shooting situation at a high school in Littleton, Colorado." We were living in Atlanta and getting ready to move to Colorado.
As a nation we watched the horror unfold with images beyond anything we ever imagined.
The whole world was shocked.
The day after the shooting I got on a plane to go to Madrid, Spain where I would lead a group of missionaries in a workshop. I had a layover in Brussels, Belgium. The shooting was on the front page of the papers there.
The feeling was indescribable as we drove past the high school and visited Clement Park. We visited Colorado a month later in preparation for our move. The yellow crime scene tape still circled the school.
The pain will never go away.
Now, after having lived in Colorado, I'm privileged to have some friends who were in school that day. They still find it difficult to talk about 25 years later. On this anniversary, lets remember the the families who lost loved ones and those who experienced that indescribably trauma.
Don't make them talk about it, if they don't want to. Just let them know you remember. There is a huge hole in their lives. A piece of them is missing. Everyday they live with that reality and the anniversary takes them back to the original shock and pain of the first day.
This is true for every anniversary.
My good friend Jason Mueller shares a similar tragedy with the people from Columbine. His son was murdered on April 20th. It was six years ago and Jason replied to my text, "It has been a long week." He thanked me for the love and support. Then he said, "Just keep us in your prayers. Also please pray for the young man who pulled the trigger. His life changed that day as well and my prayer is he finds the Lord and comes out a saved man."
The feeling of emptiness can be a precious gift.
If you are surprised by the pain of anniversary, I hope this helps you understand. If you are with someone going through that pain, just be present with them on their anniversary--listen to their stories, sit with them in their pain, cry with them. The pain and the memories reveal the truth in the Columbine banner, Never Forgotten. Anniversaries are painful but reveal the lasting impact of the value of their lives and the piece of our lives that is missing.
Deitrich Bonhoeffer gives us hope that the feeling of emptiness has value and over time become a precious gift.
“There is nothing that can replace the absence of someone dear to us, and one should not even attempt to do so. One must simply hold out and endure it. At first that sounds very hard, but at the same time it is also a great comfort. For to the extent the emptiness truly remains unfilled one remains connected to the other person through it. It is wrong to say that God fills the emptiness. God in no way fills it but much more leaves it precisely unfilled and thus helps us preserve -- even in pain -- the authentic relationship. Further more, the more beautiful and full the remembrances, the more difficult the separation. But gratitude transforms the torment of memory into silent joy. One bears what was lovely in the past not as a thorn but as a precious gift deep within, a hidden treasure of which one can always be certain."
That is not to try to give a silver lining to the loss or to say look at the bright side. There is no silver lining nor a bright side. It is remembering the great gap in your life and feeling the pain that it causes. Then in painful grief you can feel the bond with the one you lost and pray that someday, that memory will bring a mysterious joy.