https://cointelegraph.com/news/up-to-four-million-bitcoins-gone-foreverIt says up to 4 million. So that guy who lost his 103 is another statistics. Really just sad though to see someone lost a lot of money because they either don't believed that bitcoin will skyrocketed or they are just plain stupid and not backing up everything and literally throw their money away.
Can you share more about the story though? Is this a new story or an old one because we have seen a lot of people losing their bitcoins. If will be really good if you can give us a link or something.
This study is nothing more than a shot in the dark. They are estimating the number of lost coins based on the addresses that weren't used for a long time. This means that if you bought your coins 2 years ago and kept them on the same address you're probably treated like a person who lost access, which may or may not be true.
You simply can't assume that coins out of circulation are lost forever. There's no proof for it.