@DaMoshe -“…the kid was Yisroel Williger, who sang The Gedolei Hador on the album Klal Yisroel Together.”
Correct.
Trio of related singers: 1 – Avraham Fried, Benny Friedman, Simcha Friedman: 2 – Eli Marcus, Shmueli and Bentzi Marcus: 3 – Reb Dovid Werdiger, MBD, and YEEDLE Werdiger