H has a collection agency constantly taking money out of his check and he doesn't seem to care!

My husband has had this collection agency collecting on an unpaid debt for a few years. They will collect for a while and then we won’t hear from them for a few  months or so and then they will start up again. The money comes directly out of his paycheck so he can’t control it. He says it is for some court costs that he never paid dating back to 2000! They didn’t even start collecting on it until 2012 and when I first saw it, it was up to about $6000! We just got another letter in the mail saying they are collecting again. He is at the point where he says “Well it never goes down due to all the interest and it’s a legitimate debt so there isn’t anything I can do about it.” Well they can’t keep collecting all this money due to interest because they only take a set amount every time and then tack on hundreds of dollars of interest. You need to talk to someone about it. Of course he says “Yeah I really do need to talk to someone. I planned on it then forgot.” He is so damn nonchalant about all this money being taken out! There’s nothing I can do about it because it’s not under my name and I have no access to it. He will just let it continue. This last check they took out $600! Tack that on to his $300 a paycheck for CS and another $130 repaying a work loan, he’s losing $1000 a check!