As a mother who often went without court-ordered child support for my youngest daughter, and who had to wait for child support enforcement to garnish his tax returns at the end of the year, I ask you to please listen to your sister.
His actions, or lack thereof are what landed him in jail in the first place, and I know what a huge financial impact that can have on what is provided for a child. I was actually working 3 jobs at one time to support my daughter and myself.
I only wish my state had been stricter and given jail time to my youngest daughter's father.