Book about a teenage boy who has to take care of younger siblings while trying to survive from a threat

I’ve just seen Mosley lane(criminal minds) and in that episode theres a 15 year old named charlie who has to take care of his young ‘siblings'(they’ve all been abducted) and he ends up shooting their abducter at the end of it.

Now that episode was great, but it didn’t focus much on the kids relationship or the aftermath. I like to see what wouldve happened afterwards. Would the kids have kept in touch?

I don’t mind if it’s a zombie apocalypse or they’re running from something.

by AndthenIwhispered