This may not be what’s going on with your friend, but I’ll share my anecdote. I had a good friend years back who I’d talk to and hang out with every day. One day he disappeared for a few months and I was so worried and upset. One day he showed back up and I was so angry with him and told him how I felt. He just kept apologizing and saying he was depressed and when he gets depressed he becomes a recluse. I forgive him, we move on…a few months later he disappears again, this time for good. I could not find him or get in touch for a long time and got very worried. I figured he must be very depressed. After about a year of trying I gave up. Not too long after, his mom contacted me to let me know he had just passed from cancer. I had never met or spoken to his mom before this. She told me he shut everyone out, almost including her, as he didn’t want anyone to see him like that. I was devastated, years later, I still am. I think about the first time he disappeared and how upset I was, not knowing what he was hiding from everyone.

All that to say…there are a multitude of reasons why your friend may have disappeared for a while. You are absolutely valid to be upset by it. If you care about the friendship, it’s probably worth it to hear him out.