The writer started off with ethnic appeal which makes reader believing himself an expert in the field and bothers to continue to read the letter.
The writer used his son as an example in the result of gun ownership causing deaths. This can effectively create emotional appeals. As Pathos emphasis "experience", it will give the reader a perspective viewed from the one writing the letter.
Apart from all the statistics which weighed why the law on gun ownership should be changed politically, John reasoned why it is not correct to mention owning a gun as a self-defense excuse. He also reasoned why having a gun means more assaults and more risks of injuries and death.
John gives logic behind his point of view. He gives supporting evidence like gun misuse, homicides and why it is not justifiable that having a gun can prevent intruders.