Shubael was the oldest son in the family line of Gershom.
The sons of Moses were Gershom and Eliezer.
Rehabiah was the oldest son in the family line of Eliezer. Eliezer didn’t have any other sons. But Rehabiah had a great many sons.
Here are the other members of the family line of Levi. From the sons of Amram came Shubael. From the sons of Shubael came Jehdeiah.
The 13th was for Shubael and his sons and relatives. The total number was 12.
From the sons of Heman came Bukkiah, Mattaniah, Uzziel, Shubael, Jerimoth, Hananiah, Hanani, Eliathah, Giddalti, Romamti-Ezer, Joshbekashah, Mallothi, Hothir and Mahazioth.
Shubael was from the family line of Moses’ son Gershom. Shubael was the official in charge of the treasures.