Harry Nilsson's "I'd Rather Be Dead (Than Wet My Bed)" was designed for nursing home sing-alongs, and was recorded at one. That said, it's probably not appropriate to use...
For what it's worth, last winter I sang with a caroling trio at a retirement community's country club, and the patrons had lots of early to mid sixties requests. Love theme from Dr. Zhivago, Funiculi Funicula, "anything from Fiddler on the Roof," and a big singalong on "Those Were the Days, My Friend."