I'm sure he was briefed that it was going to be unavailable that day for a training mission/photo op. Was he briefed on the specifics... dunno.
I'll use this analogy- say you have to turn in the Squadron CC's car in for scheduled maintenance. Are you going to brief "Hey boss, you won't have your car today Veh MX has some scheduled maintenance to do on it."?
Or are you going to brief "Hey boss, no car today. Veh MX has to change the oil, gap the sparkplugs, check the timing, rotate the tires, replace the air filter, turn the drums, and replace the brake pads."?
I'm guessing you're going to go with brevity. Now if the car is getting routing MX done that includes getting the roof painted with the dixie flag then you may want to go ahead and brief that detail. Just like the detail that the aircraft will be doing low levels over lower Manhattan. What may seem minor and inconsequential to you may not be so inconsequential to others.