Three short lines, and a whole scene. The title, "Viewing," points to a wake or funeral viewing, where a body is laid out for people to see. The poem gives us the dead man only as "the dead servant," and that label is the first clue: even now, he is defined by his job, not his name.
The odd, quietly funny detail is "all morning dutiful." The word suggests he is still on duty, as if lying there in his waistcoat were one more task he is carrying out faithfully. Death hasn't released him from the role. The waistcoat, probably part of a uniform or his best clothes, sharpens the sense that he has been dressed for service one last time.
The speaker never says what they feel, and that restraint is the point. The mood is hushed, dry and a little unsettling, with a thread of sadness and mild irony underneath. We're left wondering who gets to rest, and who is still working even in death.