I'm not 40+ but a couple months ago I tracked down my childhood best friend after not interacting with her for almost 15 years. We went out for tea and had a great talk.
We had been best friends from kindergarten to 8th grade and we were inseparable. She said she had tried to find me multiple times after that, but she couldn't because I don't use social media.
I hadn't reached out til now because of my anxiety and other issues, but I'm in a good place now so it seemed like a good time to do it. I'm really glad I did. Maybe your friend had similar problems