This is not what it looks like. The county sheriff does not have any control over children. They only investigate crimes against children. FDCF has all the control. FDCF is a state agency that operates with many contractors (i.e. ChildNet).
The Broward County sheriff is pretty much the de facto county police because most of the municipalities in Broward no longer operate their own police departments. They have extended contracts with the sheriff to provide police services. This is also a very deep political rabbit hole that involves many millions of dollars and a whole lot of corrupt liberals in public office.