My Xbox Live friend suspiciously disappeared

So there’s a guy called BucklingChair39 who plays a lot of minecraft, like me. We used to be very good friends via xbox live, but suddenly one day, he went offline without a word. I tried re-friending him, but the friend button just doesn’t work. Anybody have the slightest idea what could have happened?

Seriously, it’s been 3 months without a sound.

:)