obbi Kristina's Friend Who Found Her in Tub Died from Fentanyl Overdose

Max Lomas -- the friend who discovered Bobbi Kristina submerged in a bathtub with a toxic mix of drugs in her system -- died from a fentanyl overdose himself ... TMZ has learned.

Law enforcement sources tell us Lomas' official cause of death was "fentanyl toxicity," and his death was ruled accidental. We broke the story ... Lomas died of an overdose in Mississippi earlier this year, but it was unclear at the time what drug had caused it. 

As we've reported ... Lomas was the guy who found Bobbi Kristina lifeless in a tub all those years ago, which eventually led to her death after she was taken off life support. A bunch of drugs were later found in her system.  

Lomas was ID'd by some authorities as Bobbi Kristina and Nick Gordon's drug dealer, but he denied that. He was at their home in the hours leading up to her death. 

His fentanyl overdose is telling in the wake of multiple overdoses over the past few years that have affected both celebrities -- male and female -- and the public alike. Epidemic is an understatement.