a guy broke into my sister's house

[realism101]

11. Your sister is not very smart.

Most personal defense courses tell you to avoid confrontation in the first place. Even NRA courses begin by teaching people to avoid confrontation. Instead, your sister walked right into it. Even though she's not very bright, she is most definitely lucky. Had the person actually been an armed or dangerous intruder, she would likely be injured or dead. She should have called 9-1-1 immediately and waited for the police to arrive.

Just because someone has a gun in their house, doesn't mean they turn into cold-blooded killers that shoot at anything that moves. This is just like the concerns about states that allow carrying HCP's into bars. Those bars have simply not turned into the wild, wild west. Otherwise, we would hear a lot more about it.