Non-Custodial parent requesting modification. California?

Will child support be reduced because the child’s father had 3 children by 2 different women? I have 100% custody; the father never sees my daughter and is required to pay 473 a month which was based on $10 an hour 3 years ago because he was unemployed. He currently works as a correctional officer in NV and requested a modification because of a decrease in income but I know it’s because his wife doesn’t work and he has 3 kids that he supports. Why would it be reduced? It’s not my child’s fault he keeps making children and can’t take care of them. Does the court really reduce child support because of this? Take away from 1 child to feed another? If this is true I wish car loans did that. I’m sorry Wells Fargo I bought another car so now I need a reduction in my monthly car payment cause I can’t afford to pay the other car loan company and you too. Thanks for any responses in advance.