Absolutely! The courts take the view that it takes two to tango, that both have made mistakes, but they both need to come to the table to sort out the mess.
It's possible that there was an interim decision that the mother would have temporary custody, or that it was joint custody with the mother having day to day care of the children. If the father made an application for 50% care of the children, that could result in termination of child support payments, and the children constantly going back and forth between two homes. If the parents do not currently live in the same town, that means a big mess regarding schooling, friends and a stable environment for the children. Parents lose rights when they divorce because the best interests of the children trumps their personal interests.
Regardless, the courts believe that it is important for children to have access to both parents, even if the parents are not perfect, and the belief is that although a parent may treat a spouse poorly, that does not mean they treat the children poorly.