The attorney is a judge too....?

My brother in law hired an attorney to represent him in a custody case. The custody case has been long drawn out and very volatile. My brother in law's ex girlfriend has custody of the kids and it has been reported several times she is doing drugs, living with a bad guy etc. My brother in law gathered as much information as he could on the girlfriend and her current beau...gave it to his lawyer, and the lawyer claimed he did a thorough investigation and neither had criminal records so there was little he could do. Now we come to find out that the current beau has been arrested and incarcerated for of all things- a sex offender (he got caught because he was arrested for child endangerment)...we went on to further find out that my brother in laws attorney who is also a part time judge had been the magistrate in all of this guys current cases so he had to have known for at least the last 6 months that the guy indeed did have a record(just not in Iowa--his failure to register and sex offender charges came out of California...lewd acts with minor and forced intercourse) yet the attorney falied to ever tell my brother in law. my brother in law has been suspecting abuse for the last year and has reported it to DHS, the judge and his attorney (all who told him there was nothing they could do without proof)meanwhile the kids throw tantrums every time they are returned to their mother, the 8 year old has uncontrolled bowel movements, they are acting out in school etc...his kids have been put through hell and now that all this has come to light the attorney wants another 3 grand on top of the 3 grand my brother in law already paid to "get the kids out of the situation he knew about for at least 6 months and that has been going on 2 years....the kids are safe for now(we hope)...the abuser is far away in a california prison...but not for long and the girlfriend is planning on having him come back to Iowa as soon as he gets out......what can my brother in law do legally???? This custody battle has already bankrupt him as he had no money to begin with.....he cannot afford a new attorney and the one he has...has not only not done a thing but he claimed he investigated the guy and the guy had no record meanwhile he was the magistrate judge in the guys extradition and child endangerment case!!!!