Matthew Perry's stepfather has said the Friends actor "felt like he was beating" his years-long struggles with addiction before his death in October.

"But you never beat it, and he knew that too," Keith Morrison said.

Perry, who openly spoke of his alcohol and substance misuse, was found unresponsive in his hot tub, at age 54.

An autopsy report listed the effects of two drugs - ketamine and buprenorphine - as well as coronary artery disease and drowning as causes of his passing.

The report also said Perry had been "reportedly clean for 19 months". But he was also said to be in the midst of a ketamine infusion therapy to treat depression and anxiety.

Mr Morrison, who married Perry's mother Suzanne when her son was 12 years old, said that raw grief from the loss nearly five months ago is with him every day.

"It's with you all the time," he told NBC broadcaster Hoda Kotb on her Making Space podcast. "And there's some new aspect of it that assaults your brain, and it's not easy."

The long-time Dateline NBC correspondent said that his stepson was in a good place when he passed.

"He was happy, and he said so. And he hadn't said that for a long time," he said. "It's a source of comfort, but also, he didn't get to have his third act, and that's not fair."

The interview with Mr Morrison, 76, was the first time he has opened up since his stepson's death.

He was photographed arriving at Perry's home with his wife on the night the actor died.

Getty ImagesKeith Morrison says 'the echo' of his stepson stays with him every day

Mr Morrison spoke fondly of watching Perry grow into a "very fiery personality" and feeling "the echo" of his larger-than-life presence in even mundane moments.

"He was goofy. He was funny. He was acerbic," he said. "But even if he didn't say a word, he was the centre of attention."

"In a way our personalities were, as they say, chalk and cheese. He was loud and out there and funny and aggressive," he said. "But we got along fine."

"I never tried to replace his dad, but I was there for him, and he knew it. We were close," he added.

Fighting an addiction "so virulent" while being in the public eye was difficult for Perry, according to Mr Morrison.

"He came to understand he'd get to a certain point, and then he knew he had to go and get treatment. And he'd accept help when he needed it," he said.

"But as he said himself, it just kept happening, and it was, it was a big bear. It was a tough thing to be — a big, terrible thing."

Perry was candid about his road to sobriety and grew into an outspoken advocate for substance use treatment.

In the wake of his death, his mother and stepfather started the Matthew Perry Foundation to help those struggling with addiction.