Story highlights Chi Cheng co-founded the Deftones in 1988

"His heart just suddenly stopped," his mother writes

"He left this world with me singing songs he liked in his ear," his mother says

Cheng and his group won a Grammy for best metal performance in 2001

Deftones bass guitarist Chi Cheng died Sunday morning, five years after a car crash left him in a coma, his mother announced. He was 42.

"This is the hardest thing to write to you," Mom J, the name his mother used with his fans, said. "Your love and heart and devotion to Chi was unconditional and amazing."

Her statement was published Sunday on OneLoveForChi.com , a website established to communicate with his fans and raise money to help care for Cheng since his disabling accident.

"He was taken to the emergency room, and at 3 a.m. today, his heart just suddenly stopped," his mother said. "He left this world with me singing songs he liked in his ear."

Cheng co-founded The Deftones, a Sacramento, California, alternative metal band, in 1988.

"I know that you will always remember him as a giant of a man on stage with a heart for every one of you," Mom J wrote. "He fought the good fight. You stood by him sending love daily. He knew that he was very loved and never alone."

Cheng and his group won a Grammy for best metal performance in 2001.

The Recording Academy President Neil Portnow called Cheng "a powerful bassist who was larger than life on stage."

"Although the group's early years were more heavy-metal-based, they were one of the first bands to incorporate a more alternative and ethereal sound into their thunderous and visceral music, blazing a trail that newer bands continue to follow today," Portnow said. "The music industry has lost a proud and passionate performer all too soon, and our sincerest condolences go out to his family, his bandmates, and his fans worldwide who are mourning his untimely and unfortunate passing."