Unfortunately this discussion is based on a very limited awareness of the sources and consequently the assertions and conclusions are not very accurate. Sincere yet uninformed pronouncements about rodef and mesira are not very productive. This is not an area for conjecture and wishful thinking – especially when the material has already been organized and translated.
I just published two volumes on the subject
“Child & Domestic Abuse” Volumes I & II
available on Amazon. Volume I is a practical guide according to halacha as well as a description of the psychological and legal realities.
Volume II is a collection of the sources in both Hebrew & English. It includes the views of Rav Eliashiv, Rav Moshe Halberstam and many others.
If you really want to do the right thing than you need to study the subject – the halachic views, the psychological, legal and sociolgical. The well being of your kids is at stake.