The Shadow Box by Michael Cristofer

In this dramatic triptych, three terminal cancer patients dwell in separate cottages on a hospital's grounds. The three are  visited by family and close friends:

Agnes and her mother Felicity, estranged further by the latter's dementia;   Brian and Beverly, whose marital complications are exacerbated by Brian's new lover Mark:    Joe and Maggie, unready for the strain of Joe's impending death and its effect on their teenager