How to proceed when next of kin/representatives are negligent and potentially abusive/exploitative?

I befriended a man who is 65 & is a 30 year Parkinson's Disease patient. I would not consider myself a "caregiver" but I helped him with everyday things about 1yr ago. I would clean for him 1x a week. These visits developed into me seeing him up to 4x a week. I would get us take-out, get mail from the mailbox, help take out trash, install grab bars, etc... I simply wanted to see his struggle lifted, even if only slightly. We eventually developed a genuine friendship. He did not pay me for my deeds, but he was gracious to me with financial gifts (money gifted to me was never for a "certain" thing). I found him in his home unresponsive and called 911. He has two estranged adult children who have no part in his day to day life. I notified them. Now, they have blocked me from obtaining his medical condition- despite knowing that would break his heart. They have also initiated a DHS investigation against me. What can I do if legal rep's do not have the best interest of the patient?