Why doesn't Mr. White want Mrs. White to see her son, Herbert, after the death and when the wish is asked in "The Monkey's Paw"?

The author has already revealed that Herbert has been
mangled in the machinery at work, so we can assume that his body is no longer the way
the Whites remember him. When Mr. White made the second wish--"I wish my son alive
again"--he did not fully comprehend the possibilities, just as he had not considered the
awful implications that could come with the first wish. He had been badgered by his wife
to make the wish out of their own sadness and desperation. Only after he makes the
second wish and hears the knock on the door does Mr. White realize that the knock comes
from Herbert--and that he will be in the same state in which he died, not as the healthy
son they remember. Mr. White understands that if he opens the door, it will be the
returned-from-the-dead Herbert, complete with the terrible injuries he received in the
accident; so, he makes the third wish--presumably that Herbert be dead once again--in
order to spare his wife from any further horrors.