Since storming the charts in 1967 with the remarkable “The Rain, the Park and Other Things,” the Cowsills have been oft-overlooked in the annals of rock history, dismissed as nothing more than bubblegum. And it is this heartbreaking story of a family group — a genuine musical entity — that sheds a greater light and depth into this fascinating act. Narrated by Bob Cowsill (guitar, keyboards and later, lead vocals), Family Band: The Cowsills Story is a portrait of musical vision, family unity, desire to grow, pain, firings, financial mishandling and worst of all, abuse on all levels by their father, Bud Cowsill, who was their manager/tormentor. Initially led by oldest brother, Bill on lead vocals and guitar, The Cowsills were not musical lightweights; their skill as musicians (especially Barry [bass] and John [drums], who were just children when the band actually started) cannot be underestimated and their celestial vocals are no less than “angelic psychedelia.” There are moments in this documentary that make you uncomfortable; the music lifts you up and the tragedy of both Barry’s passing (in the aftermath of Hurricane Katrina) and Bill’s passing a few months after simply move you to tears. Told in a warm and lighthearted manner, considering having to relive the pain with his surviving siblings, Bob Cowsill’s telling of their story is powerful and riveting.