The Subject was Roses by Frank Gilroy (1965)

Summary:  John and Nettie Cleary have just welcomed their son Timmy home from World War II.  As such, there are feelings of happiness, relief and the awkwardness that accompanies the return of a third person to a two-party household.  As the play progresses, the troubled nature of each relationship in the play (John and Nettie, Nettie and Timmy, John and Timmy) is illuminated.

Thoughts:  Again, a play where not much happens outside of the small New York apartment where it is set over the course of one weekend.  This family doesn’t have horrendous problems, but they have clearly never talked openly about the interpersonal issues that they do have.  Upon his return from war, Timmy is drinking perhaps too much, making grown-up decisions about his faith and future…and his parents are clearly not ready to let him go after just getting him back.

"[The Subject was Roses] is my signature play, for which I am grateful.  But my dream is some day to be introduced as the author of something other.  So far no cigar, but it ain’t over. 
The Pulitzer guarantees the first line of my obituary. 
I wouldn’t give it back.  But it screwed me up for several years as you’ll see."

-Gilroy’s introduction to this play in Frank Gilroy Volume 1 (Smith and Kraus).