About what does Uncle John feel guilty?

Uncle John feels guilty about his wife's death. She was four months pregnant and suffering from terrible stomach pains. Uncle John blew it off and told her she must have eaten too much.... to take some pain medicine. He refused to call the doctor. Unfortunately, he was wrong, and she ended up dying from appendicitis. He never forgave himself.

Uncle John’s guilt is a result of his wife’s death. He is trying to make good with what has happened, “He's all the time makin' it up to somebody (69)”. Unfortunately, his acts of service to others will not change what happened; he cannot go back in time and fix the past, no one can. That is part of what makes his backstory so sad, the fact that there is nothing he can do. Uncle John is not happy because of what happened, even though his acts of kindness, “…an' still he ain't very happy (69)”. He will never be able to be happy until he can forgive himself. It doesn’t matter how many other people tell him they forgive him, or that he needs to stop beating himself up about it. This is true in real life as well, the second someone learns to forgive themselves, is the second they can stop the misery that goes along with guilt.