LORELAI: She’s been acting so weird lately. They’re fighting. Openly fighting. I don’t think they’ve ever done that before. I’m not sure what to do about it.
CHRISTOPHER: Move to California. That’s what I do when my parents fight.
This apparently explains why Christopher moved to California, to get away from his parents’ fighting. From what we saw of Francine, she was far too cowed to look as if she ever fought with her husband, but perhaps she’s been thoroughly brow-beaten into submission by now. Most likely, this is another of Christopher’s lies, used to justify his behaviour.
Lorelai has supposedly never seen her parents fight before – if so, they must have been very careful to keep serious conflict hidden from their daughter while she was growing up to give her a stable home environment. However, this is the same Lorelai who claimed she and Rory never had a fight until Rory was nearly sixteen. She’s possibly just forgetting all the previous fights her parents had.