What did Father want to do about the newchild?

The first answer does not say anything wrong, but I wonder
if you are not asking about what Father wants to do with Gabe late in the
book.

At that point (it's p 164 in my copy, Chapter 21),
Father wants to release Gabe.  As the first answer says, he had brought Gabe home to try
to get him to be less fussy.  But it hadn't worked.  Gabe had been given to a family on
a trial and he cried all night.  So even Father has voted to release
him.

When Jonas finds out that father wants to do that, he
takes Gabe with him when he leaves.

So my answer would be
that Father wants to release Gabe, the newchild.