NEW BIOGRAPHY — DEAD MAN'S CURVE: THE ROCK 'N' ROLL LIFE OF JAN BERRY, by MARK A. MOORE (McFarland & Co., 2021)
That's footage from PBS. It aired nationally.
I think they buried Jan's voice, covering it with another voice.
Plus, he didn't live the healthiest lifestyle, especially given his limited mobility.
He didn't get enough exercise.