Where does Bob Ewell demonstrate that he does not care about anyone else but himself in To Kill a Mockingbird?

While Bob Ewell is on the witness stand during the trial of Tom Robinson (Ch. 17), some of his responses to questions indicate that he is unconcerned about others. His actions after the trial underscore how he serves his own self-interest, as well.

Before Ewell begins his testimony, Scout's description of where the Ewells live also indicates that the father neglects his family. The cabin that they live in does not even have glass in the windows; the children have hammered tin cans flat in order to form a roof, and made shoes of things found at the dump, as well. These neglected offspring of Ewell are not made to attend school except on the first day. The children have no health care:

...no public health officer could free them from...various worms, and the diseases indigenous to filthy surroundings. (Ch.17)

While Bob Ewell is on the witness stand, he crudely compares his daughter's scream to that of "a stuck hog inside the house," yet he does not bother to call a doctor to treat her facial and other injuries, despite his accusations that Tom choked and struck her. In fact, Ewell seems unconcerned about Mayella's bruises on her face. Also, he boasts that he has never called a doctor for his children because doing so would cost him five dollars.

Of course, having made Tom Robinson a scapegoat for Mayella, who has broken the social code with her act of kissing Tom, Bob Ewell has no qualms about accusing this innocent, charitable man of the unforgivable crime of raping a white woman, an offense whose punishment is certain death. While on the witness stand, Ewell stands and points at poor Tom, crudely growling out, "--I seen that black n****r yonder ruttin' on my Mayella." Yet, he knows full well that Tom has done nothing wrong; instead, he has tried to help her because her father is so neglectful (Ch. 19).

After the trial, Ewell wishes to retaliate against Atticus for having destroyed some of his testimony with contradictory facts and for, he feels, having tried to embarrass and humiliate him and Mayella. In the most despicable act of his life, Bob Ewell tries to kill the children of Atticus Finch (Ch. 28-31) in retaliation for what he perceives as Atticus's badgering and ridiculing of him on the witness stand.