If it's only for unpaid fines you should be able to post his bail and get him out. It may be cheaper, however, to pay off his fines. Your choice.
Without making any statements or admissions related to payment of fines, you should contact each probation department to find out how much of a payment would be necessary for them to lift the warrant. Make sure you get the person's name who gives you this information. If you're able, pay the fines necessary for release. This amount may not necessarily be the full balance, but just the required payment to get him caught up. I doubt your husband has a bond, but if he does it seems you'd be better off using any money you have to pay off fines.
Otherwise, he will have to wait for a probation revocation hearing to be scheduled. Your husband has a right to request a lawyer for a probation revocation proceeding where the judge will decide whether the circumstances require an attorney under due process of law. At this hearing, careful arguments should be made related to his (in)ability to pay the fines as a defense to a probation violation, or attempt to reach a stipulated agreement with probation as the scheduling of future payments.
If you'd like to hire an attorney to assist you further through these proceedings, I'd be happy to speak with you. Good luck.