AIR TRAFFIC CONTROL AT REAGAN INTERNATIONAL AIRPORT: Should 2 controllers always be on duty?

It seems weird to me that there is only one air traffic controller at night for Reagan International Airport. I can see this at a regional airport, but at a major port? What if something happens to one, like a heart attack? Will the janitor find him in the morning? Seems it is necessary to have 2 or 3 pilots for every airplane, so why not at least 2 for a tower, at all times for major airports? This guy has been on the job for 20 years, give him a buddy! Hope he is not fired for a policy that should have been different at Reagan International Airport. Visit an ad on my blog if time permits. Thank you!