"Why on earth would he retire from that job so early?"
NWtreehugger didn't say her DH was retiring at 55.
The last company I worked for hired a new manager that was a piece of work. People left, they didn't replace them. They just dumped their workload on the rest of us. Customers started getting angry about poor service. Eventually, all us experienced office staff left. This business shrunk and shrunk. Now they have moved to a smaller place with a smaller customer base. Closed down sales and service department. Lost their "counties best" reputation. Now, when I hear them mentioned in public, it's negative.
Ask your DH if his boss works as hard as he does. If not, when times get better, your DH might be better off finding a job elsewhere. My DH had a four year stint in the armed forces as a second, and then first, looey. Officers at that level haven't yet forgotten that being a leader means taking care of the troops primarily, so that they can accomplish the mission.