Grateful Dead stars Bill Kreutzmann and Bob Weir have praised their former bandmate and “brother” Phil Lesh for changing their lives.

The bassist, who was a founding member of the US rock band alongside Weir, Kreutzmann, Jerry Garcia and Ron “Pigpen” McKernan, died age 84 surrounded by his family on Friday.

The group became know for its fusion of genres including rock, jazz and folk which contributed to the countercultural generation of the 1960s.

“Phil Lesh was my brother. Not by blood but still by family”, Kreutzmann wrote on Instagram alongside a photo of the pair from their younger days.

“I’ve heard so many of you tell me that the Grateful Dead changed your life. Yeah, well… Phil Lesh changed mine.

“Phil turned me onto John Coltrane. Back in the early days of our friendship, he wasn’t just like a brother to me – he was like an older brother. A roommate. A bandmate. A mentor.”

He continued by reflecting on how lifelong friendships and family relationships are “complicated and dynamic” but will “ultimately stand the test of time”.

“So keep only the good memories, for they are the only ones that matter. That’s what I’m going to do. Because love is real, not fade away”, he added.

“Thank you Phil. I’ll miss you, darn it.”

Weir posted a collection of photos of him performing with Lesh on stage over the years to Instagram as he also reflected on how his late bandmate influenced him to the John Coltrane Quartet.

He revealed Lesh had introduced the group to the “wonders of modern classical music” and said their discussion around the genre helped him “grow”.

“Concurrent with all this was the ongoing conversation about the things (ideas) we present outside of music, and the effect it would have in shaping the world around us – let’s just say Phil wasn’t particularly averse to ruffling a few feathers”, he added.

“We had our differences, of course, but it’s not platitudinous to say that that only made our work together more meaningful.

“Our conversation and interaction will last, at very least, ‘til the end of my days.”

Weird signed off his tribute by writing: “Meanwhile, given that death is the last and best reward for a life *well and fully lived*, I rejoice in his liberation.”

A statement posted to Lesh’ Instagram said on Friday: “Phil Lesh, bassist and founding member of The Grateful Dead, passed peacefully this morning. He was surrounded by his family and full of love.

“Phil brought immense joy to everyone around him and leaves behind a legacy of music and love. We request that you respect the Lesh family’s privacy at this time.”

He was best known for the song Unbroken Chain, about the counterculture band’s connection with its audience.

Lesh also sang the wistful Box Of Rain, which he wrote while his father was dying.

He disclosed in 2006 that he had prostate cancer, and had a liver transplant in 1998 after a hepatitis infection.

The Grateful Dead disbanded after lead singer Jerry Garcia died in 1995 at a drug rehabilitation clinic, aged 53.

Other members to have died include Brent Mydland in 1990 of a drug overdose, McKernan of liver disease in 1973 and Keith Godchaux in a 1980 car crash after he left the group.

Mickey Hart, from left, Bob Weir, and Bill Kreutzmann (Danny Moloshok/Invision/AP)

Lesh also toured with the band’s spin-off groups including Other Ones, The Dead and Furthur, and his own group Phil Lesh and Friends.

On Wednesday, music foundation MusiCares announced it would honour Lesh along with other former members such as Kreutzmann, Mickey Hart and Weir as its 2025 Persons of the Year for their charity and campaign work.

Kreutzmann said that Lesh and the other members were going to attend the 34th annual Persons of the Year benefit gala, where they had planned to celebrate their 60th anniversary, and pay tribute to Garcia.