Mr. Henderson is the landlord of the apartment building, and lives in his own room on the ground floor. He is a war veteran, and is first mentioned once Sam picks up some rent money in his apartment.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...