VANCOUVER – The singer of one of B.C.'s best-known rock bands has died at age 57.

John Fraser Mann, lead singer of Spirit of the West, died in Vancouver on Wednesday from early onset Alzheimer's disease, which he was diagnosed with several years ago.

"John was a man of uncommon courage, was a loyal and beloved friend, a gentleman of great social conscience, and a soul brimming with creativity and enthusiasm," said a statement on the band's Facebook page. "Most importantly, he was a loving father to Harlan & Hattie and a wonderful husband to Jill Daum."

The band was perhaps best-known for its song Home for a Rest. Mann's career spanned nearly 40 years, and he received the Order of B.C. in 2016.

"I think a lot of fans of Spirit of the West in Canada sadly knew that this day would be coming, but everybody thought that it would come a lot later," said Spirit of the West publicist Eric Alper. "What an amazing man. What an amazing father. What an amazing husband, artist and spirit."

Mann had been the subject of a documentary, "Spirit Unforgettable," which profiled the band preparing for a 2015 concert at Toronto's Massey Hall as part of their farewell tour as Mann dealt with the impact of his diagnosis.

"He's so valiant, and he works so hard to wring out what he can from every day," Daum said in a 2016 interview with CTV News, the year the film was released.

At the time, it was thought the Toronto show would be the band's final concert, but they ended up performing a three-night series of shows at the Commodore Ballroom in Vancouver in April 2016. The band said at the time they planned to rally around Mann and were planning to organize "Johnny Jams" once a month. Mann used an iPad as a teleprompter during his final performances.

Alper said Mann's voice will be deeply missed in Vancouver.

"There's no question even though John was born in Calgary, his roots were really in Vancouver and B.C.," said Alper. "He used his power as a frontman not only with brilliance on stage but offstage as well, putting the spotlight on causes that he believed in, whether it was environmental causes or just small artistic companies that he thought were vital to the community and the City of Vancouver."

Alzheimer's advocates also commended Mann for his efforts to raise awareness about the disease.

"John was a remarkable person and a strong advocate. He approached his dementia journey just like he approached his whole life – inspiring and courageous," said Maria Howard, CEO of the Alzheimer Society of B.C., in a statement.

Alper said many musicians saw Mann as a "hero" for being so public with his health issues.

"Surrounded by friends and loving family until the end, all were reminded of John's rich legacy. He was a potent force in music, acting—onstage, in movies and on television, and was world renowned as a songwriter," said the band's statement. "As well, he was a foresightful activist and charitable figure for several worthwhile organizations. His work will resound long after his untimely passing."

Mann had also battled colorectal cancer before being diagnosed with Alzheimer's.

"I think John's legacy is going to be simply one of the greatest frontmen in a band that this country's ever produced," said Alper.

A private memorial service will be held at a later date.