The father is suffering more than enough. Arresting him is only going to make things worse. The child needs support, not his dad being in jail or fighting charges.
Being vindictive doesn't fix the justice system..it only makes you feel good for a moment and shitty about yourself later.
And?
The irresponsibility of the cop has forever altered the life of his child and such actions should have a penalty and probably do. Whether or not the father is suffering is not germane in the least.