How do you make a zombie care?

I'm a single mother to 4 wonderful children ages 12,10,8,7, yes i'm never bored, and i get no sick days. I split with their father 5 years ago and it has been a rollercoaster with him. He's not responsible and has no participation in school events, conferences, or their life. He only sees them 1 time a week if that. So in my eyes he's like a zombie that doesn't feel or care to be there.
I can't help but wonder whether things will ever change. I can't force him to be a father and he doesn't pay child support. I have a case open but he works under the table. It frustrates me that i can have the solution to anything else but this.
I don't know what to do for him to be more involved.
can you change this circumstance?