:( Does anyone know the divorce laws in California when a husband just walks out on a wife and his kids?

You can file a complaint for divorce and get the court's permission to obtain service of process by publication. Then you would publish a notice about your divorce complaint in a newspaper of general circulation in your county, for several consecutive weeks (typically four). After the publication, you are deemed to have obtained service of process on your spouse. Wait another 30 days to give your spouse time to respond, and then you can apply to the court clerk for a declaration that your spouse is in default.
When you go to apply the court should tell you If this procedure is done in your state