Can rehab center refuse admission of a patient?

I am caring for my grandfather who just got his foot amputated due to diabetes. His current rehab center is terrible and I am trying to get him moved to another one. However, the Admissions Office told me that they will not accept him because he is loud. His discharge paperwork from the VA says that he is "aggravated and impulsive". If I just had my foot cut off, I'd be aggravated too. Is this legal?