Child support and power of attorney?

My ex-husband has been ordered to pay child support on our daughter through the divorce. He was given no visitation rights due to his recent legal woes. He was arrested again recently for an indefinite amount of time. He asked his mother to be his power of attorney. Will this mean HE is still responsible for his bills/ the child support or does that mean his mother is now responsible. Also, is there a way to get child support from somebody if they are incarcerated?