If the property is in the parents' name, it is their personal property. Unless it involves inheritance, it has nothing to do with children in law. They want to divide the property, purely to dispose of personal property, without the consent of a third person (including the children you mentioned).

Of course there are exceptions. If parents agree in the division of real estate that the division must be signed by all children before it can take effect, then the signature of all children is a necessary condition for the division to take effect. This is in line with the principle of voluntariness.