Is it legal in the U.S. to over prescribe anti-psychotic drugs for alzheimer's patients to accelerate death?

In the UK, this is referred to as "chemical cosh." Nursing homes in the UK have given Alzheimer's and dementia patients an over prescription of anti-psychotic drugs which accelerates the dying process. I know of a case in Middle Tennessee where a doctor with Heathspring Managed Health Care has done just that with a family member of mine. He was in the last stages of alzheimer's, being cared for at home by his wife. His health was fine. His mind, however, was severely deteriorated. He was going for walks in the middle of the night and getting lost. His wife took him to his neurologist who prescribed respiradol. He became less agitated and eventually, lethargic. This increased the strain on her as he was wetting himself more and could barely feed himself. She went back to his managed health care doctor who changed the dosage on his medication and had hospice come in to his home. Now he has less than two weeks to live. Is this the "killing Grandma" scenario that Sarah Palin described in her efforts against socialized medicine? If this was your parent or closed loved one, what would you do?