How can I get my grandfather out of a nursing home?

How can I get my grandfather out of a nursing home?
My grandfather is an 84 year old man, who has been placed in a nursing home by his wife three weeks ago. She told him he would only be in there temporarily, while she underwent and recovered from gallbladder surgery. He agreed to this and allowed himself to be signed into the nursing home, and also signing over durable power of attorney papers to his wife. After residing in the nursing home for one week and not having a phone call or visit from his wife, who never did have surgery, it was becoming apparent that he was abandoned. His only son, and all six of his grandchildren, live near Cincinnati, about three hundred miles away from this nursing home. His son went to visit him, and to arrange to sign him out. He was told by the nursing home staff that only his wife could sign him out. After his weekend visit, he vowed to come back down to get him out.. He sought legal advice and was told that my grandfather could sign a paper revoking the power of attorney papers he had signed to his wife. On December 23, he was once again turned away from the nursing home, saying these papers could still not release my grandfather.