Don is Rebecca's boyfriend during One for the Road. Despite proposing to her, Rebecca subconciously replies with "no", causing the plumber to storm out of the bar. However, the plumber sees Rebecca at Melville's with Sam and then proposes again, to which Rebecca screams out an ecstatic yes, and the two quickly elope.
By the second season of Frasier, Santry has made a fortune off a plumbing-related invention and leaves Howe.