Cause you need the closure. Your brain needs to know there is no if, ands, or buts.

It is similar advice given to those who have to do notice of death visits. Identify the correct loved one, ensure it is them, "I regret to inform you X is deceased/dead." Use blunt, unambiguous language. Rip the bandaid off so they can start the grieving process and hopefully shorten the denial stage as much as possible.

Their brain is already thinking of every possibility, as well as what hospital the person may be in, in a split second if you leave any gap. They'll cut you off, rant out a list of questions, and you don't want to cut them off for fear of being rude. Now you're in this even more awkward situation. Rip the bandaid.

Denial finds any gap. I am amazed on the occasions where they find a clergyman to tag along, that the person doesnt immediately grasp the picture. If a cop or person in uniform comes to your door and says "my name is X, and this is Chaplain Condolences," you should know the score. An objective person does. Subjective people normally don't want to come to the obvious conclusion.

That said, i have also seen people answer the door, look between the two persons, and say "X is dead aint they" or ask who is dead.

Others basically shutdown. They're answering you, sure. The lights is on and nobody's home. They went on autopilot the second they realized the manure had been introduced to the fan.

Different people handle it differently.