What action can I take against a substance abuse treatment for not providing appropriate medical care to my loved one?

I just don't want this rehab to neglect future clients, who don't have anyone to advocate for them. I'm a health care professional. I believe the rehab medical coordinator is either incompetent or neglectful. My loved one has been sick since Monday and has yet to be treated adequately. On Tuesday he saw a doctor who suspected he could have a deep vein thrombosis, which is the main cause of pulmonary embolisms. It is considered a emergent situation. Against the doctors orders to get an ultrasound immediately, the rehab waited 4 days to take my loved one to get an ultrasound. His ultrasound was negative for blood clot, but he is still in pain and his foot is so swollen he can't even wear his crocs. He probably has cellulitis or some sort of infection/inflammation. This is day 5 and he still has not seen the doctor again because the rehab doesn't have time to take him. Also he's had 3 open heart surgeries, blood clots in his legs and arms, and he had a mechanical heart valve. The rehab was aware of this before he was admitted.