If he divorced LH and little Cooper was alive, big daddy would have to pay child support and likely need to visit his child. sorry excuse to kill imoo.
It is difficult to think that they were planning on divorce because of her comments wt the funeral. For instance, that she would have more children with him. So, divorce does not seem like what was going to happen.
But let us say they were thinking of it. Maybe they killed him so CH would not have to suffer through divorce. It could be in their church, divorce is really frowned upon.
I wonder if they are both from families where divorce occurred.