John Gill Commentary Nehemiah 3:18

"After him repaired their brethren, Bavvai the son of Henadad, the ruler of half the district of Keilah." — Nehemiah 3:18 (ASV)

After him repaired their brethren
Either the brethren of the two before named particularly, or the Levites their brethren in general, as Jarchi:

Bavai, the son of Henadad, the ruler of the half part of Keilah ;
the other half of that place.