I'm sure he was in pain, reports of hip problems and I do believe he had Aids. He was not very big person, 5'2 and thin. It would be easy for him to accidently overdose. I used to have take opiates for chronic pain and I'd forget I had taken a dose and take another. Your mind gets really blurry. I used to write down in a notebook when I took pills to prevent accidental overdose. I finally tapered off the pills and now use steroid injections and other procedures to keep pain under control.
Prince seemed like a decent person, so sorry his life ended this way.