I would at least call your local child support office and at least see if you can get an order for support. If they give you an order they can take his taxes of he files taxes plus they can cause havoc for him when he falls behind.
I would get proof of his income and nail him to the wall!
Go to court and ask for child support. But it sounds like you want full custody just so he has to pay you. Your kids are NOT pawns, they are not a means to make money. I get that money helps to take care of them but to take them away from their dad just because of money seems petty
Put him on child support like now! They will definitely make him pay job or no job. They will force him to get a job so he can help provide for his kids.
Even if he just gets one day it seems like you already have full custody, he just gets 1 day
In my case my ex was the same. They could look at what he did for work in the past and what he is capable of based on education and past work experience and you can ask the judge to input a salary for him. Unless he is injured or mentally unfit, in CA they don’t allow zero income.
Apply for child support !!! Go directly to the state. Do it now !! It’s not only your right, it’s for the kids !!
See a lawyer. He owns a house??
You can go for support. They’ll put a lien on his house too if he stays in arrears