I'm sorry to hear about that. Accidents happen. Kids should never play with guns. Teens the same, without adult supervision.
There can not be any real dialogue unless people accept the fact that guns, weapons, are a necessity. I see, myself, and I could be wrong, pure pacifism. That is not what the Buddha taught. There will always be a use for them, guns. War is ever a shadow looming over every nation. And so long as it is possible for commonfolk, scum, to have them, we will need them to fight back. And even then, the question of, what about those who get them illegally? Like say in the UK.
Guns will always exist, the only change we can hope for, is proper training for their uses. To show people all other ways of self defense, so that they can exhaust all other options before being forced to use it on another life.
Guns are not going to go away so long as the world is divided by many nations.
Guns are in the hands of deviants, throughout the entire world. Fists cannot stop a bullet.
Pure and total pacifism will only lead to tyranny and oppression. And is an excuse for cowardice.
Not everyone is a Buddhist.
Islamic Terrorists are real. They do not care for peace talks, only the death of the Kafoor. I do not need to cite evidence for that. And it is not only Islamic, there are people like this everywhere. To deny the use of guns, is to deny logic.
Everything that makes you, you, is the result of your Environment (Society, Culture, Family, Friends, Etc), Genetics/Biology (Your brain which makes the mind possible, Inborn diseases such as Down Syndrome, or even Psociopathy, etc), Thoughts (Everything you think affects your mind, and the person you are), Speech (Same as thoughts, but words affect your environment as well), Actions (Same as Speech), and the Elements (Earth, Water, Fire, Wind, Space, and Time).