Amateur (Ham) radio and CB radio are commonly mistaken to be the same thing. They are not. CB is an unlicensed band. Ham Radio is licensed and restricted.
Shiori Igawa tells Sheriff Longmire that her grandfather James had been sent to the Japanese-American internment camp during WWII and "drafted into the U.S. Army". Japanese-American internees were not subject to the draft then, but the Army did raise numerous volunteers units from the camps, so it is not unusual that her grandfather did serve.
The door hinges were on the inside of the room where the man was locked. The caretaker could have pushed the hinge pins out and opened the door.