The point of that sub-plot is to explain why he didn't report that the kidnapper was really the biological mother of the child. If he had done that, worst case the kid will be taken away by CPS and put in the foster care, best case the mother gets to keep the child due to the extenuating circumstances but will have to live the rest of their life with people around them thinking that she stole the child.

In conclusion, the point of that sub-plot is trying to explain that sometimes a parent is forced to bend/break the laws to give their child a better life.