Post apocalyptic near future

[Graeme]

A girl and her mutated sister helped by a man who can fix anything mechanical battle a cult led bynthe lightbringer
Mutants are uaually mute and dangerous. Her sister can speak and is not dangerous.
They rove over the USA looking for her father.

[Andy Phillips]

Do you know what caused the apocalypse? Nuclear? Disease? Natural disasters? Unspecified?

Does this occur relatively soon after the apocalypse? Do the kids live through it? Would their father remember it?