If you cannot afford an attorney, I suggest that your husband do the following:
1) contact the judge's office who issued the warrant
2) have the case number ready to give to the judge's assistant and/or name and date of birth
3) very briefly explain that there is an outstanding warrant and that you would like to get it taken care of (essentially, in legal speak, you are asking for a "Motion to Withdraw Capias").
Once he is in court he will ask the judge to withdraw the warrant and remove the D-6. He should be prepared to pay any outstanding costs.
Just beware, the judge can take him into custody on the warrant.
Best of luck!
Legal disclaimer: The answers given are limited to the facts as given and presumed by the answer itself. Without seeing actual written documentation or having a conference to more fully explore the issues, this short answer has only limited application. Make sure to seek legal counsel and provide all documentation to get assistance in making informed legal choices.
He needs to face the music one way or the other. Pay the fine and get the D6 clearance. If he can not afford the fine he will need to see if he can get a court date and request the fine be waived. An attorney to represent him in court would probably cost more then paying the fine and getting the clearance on his own.
He won't need a lawyer to get the D-6 clearance (that can be obtained for a small fee at the Clerk's office in the county where the violation occurred) but he may want to hire an attorney to address the warrant and attend court. If he can't afford an attorney, he can always try to file a motion as a pro se litigant, or contact your local bar association for low cost attorney services.