How can I find a probono attorney or one takes payments for an inmate in prison to fight bogus charge on him?

Husband charged with possession of three pills found on hallway floor at oklahoma work center. I was told an officer admitted to mother in law to Believe your son on him saying he is inncocent. The pills were ibuprofen prescription i do think. No actual proof of him having them, just were found on floor asked husband if were his, he said no, guards said he said were his which is a lie. Don't have much money need attorney he is appealed this and wants to take this to street court. He would have been home by Christmas, he was supposed to sighn lower security papers in July to go to a half way house to work then get to come home. He has served all his charges but one. His # is 122368 oklahoma doc offender lookup. I need someone's help. Governor Henry has not contacted me on this , trying to get a pardon for him. I don't know who to turn to and don't have much money for an attorney as I am drawing my unemployment and have two daughters and two grandbabies I try to take care of. I hope someone can help my husband.