looking4light113,
zachira has asked some important questions as it greatly affects how you may want to handle this.
This:
The most important thing is you do tell the children that the disappearance of their grandmother from their lives does not have anything to do with the children, as they might think they are at fault.
Yes, you want to make sure that above all else they know they are not at fault in any way.
In general, I would say be as honest as you can (in an age appropriate way) without sharing explicit details. Remember, you are setting an example that your children will likely remember for the rest of their/your lives. It’s good for them to know they are loved and that your immediate family (you, your husband and children) are the focus of your care and concern. (Grandma is an adult and responsible for the consequences of her choices and actions.)
Thinking of you and sending positive energy and love your way. You are worthy of love, goodness, peace and joy in your life.
L2T