Unfortunately, I don't KNOW, personally, of any lawyers who will take on causes for the disabled and advocate for them (YET~!). There ARE many lawyers listed at the fight.cps site, but most live in larger cities, want a BIG retainer up front, and I've found only ONE who really loathes CPS. And, there are a LOT of "elder law" attorneys who will take on nursing homes.
Since the issues for the disabled are usually out of the CPS arena, but in the APS baliwick, this is a different animal. (APS is the big sister agency to the not always truthful little sister, CPS and I've found neither to be responsive). When you appeal to the ARC (at the State, not local level), the State or Advocacy, Inc., they often toss the ball around to each other.
HOWEVER, one bright light of hope, in Texas, is State Sen. Carlos I. Uresti, who sits on the Senate Committee for Health and Human Services. One of his hot button issues is the drugging of foster children and he's written legislation to deal with this. (see: http://www.senate.state.tx.us/75r/senate/commit/c610/c610.htm.
He is a lawyer, and is also sponsoring a Bill of Rights for foster children but he needs to INCLUDE the disabled in his concerns in re: drug abuse. More on this at the "Take Action" tab.
The State of Texas publishes a 16-page booklet, "Your Rights" in the HCS Program but the rights assured here are often ignored, abrogated or removed by the provider and/or any "paid professional (sic)" guardian, totally violating the Constitutional and Civil Rights of the Disabled.