Headstocks break more often than you might think. It sometimes doesn’t take much: The guitar leans against an amp, somebody walks by and accidentally bumps into it. It tips over, and from the impact, the headstock breaks off.
First, I glued it back on. Because the glued surfaces were rather small, I routed two channels inside the back of the neck were I inserted two pieces of mahogany to stabilize the area. The inserted pieces had to be shaped to fit the neck.