Ok, you're saying that if he tries to go and save his sister after SHTF he/she will likely be dead. The way you posted, it kinda came across as an "It doesn't matter you'll both be dead anyway" kind of attitude.Yes, it's the blunt truth. Prepping is great but to think you are going to save yourself and your non prepping family located on the other side of the country is ludicrous in a scenario that involves the demise of the entire country.
Or just buy a plane