Charlie Wilson just can’t be stopped. In the ’70s and ’80s, the Tulsa, Oklahoma, native helped to define classic house-party funk with the Gap Band. Along with his brothers Robert and Ronnie, Wilson—now 60—created such chart-toppers as “You Dropped a Bomb on Me” and “Early in the Morning” during the band’s ’80’s heyday. But the group’s hard-partying ways—as well as struggles with alleged mismanagement—took their toll. Substance abuse, topped off by a period of homelessness, followed, before W...