Wilson, 64, died early Sunday at Kresson View Center in Voorhees, N.J., following a stroke and a heart attack, his cousin, Faith Peace-Mazzccua, said Monday.
Philadelphia International Records, the former record company for Harold Melvin & the Blue Notes, said Wilson's death leaves Lloyd Parks as the sole surviving member of the group. The lineup also featured Teddy Pendergrass and Lawrence Brown.
The group produced a string of R&B hits in the '70s and helped define the Sound of Philadelphia.
"If You Don't Know Me by Now" topped the R&B charts and made the top five on the pop charts. The hits that followed included "I Miss You," "Bad Luck," "Wake up Everybody," and the dance track "The Love I Lost," which has been credited as one of the first disco records, according to an All Music Guide biography on the Billboard website.
"He left home at 16 as a pauper and came back home a millionaire," Peace-Mazzccua told The Associated Press. She said her cousin kept performing until a few years ago and hoped to return and sing gospel music.
"Bernard was a very funny person. He should have been a comedian," she said. "He didn't take no stuff and he loved people."
Funeral arrangements were pending Monday.