On the contrary, I find it much easier to live with guns in my house knowing that there are many criminals out there with weapons, and if one of them decides to enter my home uninvited and with the intention of harming my family, I can blow his fucking head off to protect my family. I don't call that living in fear, I call it insurance with peace of mind.
People who break into homes knowing that somebody is there only do so with the assumption they aren't armed. In this case, they probably knew the parents were gone and didn't think a 14 year old boy was a problem. Fortunately for those kids, the intruder was wrong. That boy might need a lifetime of therapy to deal with the taking of a human life at such a young age, but I'm sure he would rather be in therapy than dead, or forced to live with one of his siblings being killed.
Something does not turn good if the civil have to protect themselves against badguy. Maybe society need to be change.
Society won't change for the better in our lifetimes, it will only get worse. I always hope for the best in people, but I'm prepared for the worse. The world once had a little thing called the Cold War. The Soviet Union and the US each have enough nuclear weapons to destroy the world many times over, but neither is willing to use them because they know that whoever launches the first missiles will cause a response from the other. It's called mutually assured annihilation. The same theory works for criminals thinking about entering the home of a gun owner. They may get in, but I can promise they won't get out.