If the property belonged to him i.e., either self acquired or inherited, then it is his own and absolute property.
He can dispose it in any manner and can transfer the same to any person of his choice.
His authority cannot be questioned by anyone.
His father's property cannot become ancestral property to your children.
Moreover your children are now adults and married, if at all they feel that they hav any rights in the property for any share then it is they who who have to fight for it legally, they are not dependent on you hence you cannot fight for their rights in your own capacity as their mother.
Their rights as biological children to your husband remains even if you are divorced or remain married.
Therefore please be aware that you cannot do anything legally about this.