Need help getting my dad the medical treat he needs

Hi my name is brittany I am looking for some help on getting my dad medicinal help he needs that the nursing home he is in won't give him for his sake and my family's. My dad had a stroke 5 years ago and due to the stroke he had he can't think clearly or correctly and the nursing home said we are not allowed to bring in a doctor that is not provided by their staff. If anyone has any  tips on how me and my family can get his the correct treatment we would apperiate it to the fullest thank you