We often avoid exposing our children to unusual situations, assuming they are not ready to be exposed to life’s realities.  Mom is confused and might not remember names or may be wearing odd clothing.  Who knows, Mom may have had a bladder accident.  So when is some level of exposure alright?

Aging is a fact of life. If you are blessed with a long life it is likely that you may need a little help in your later years.  Do you want to be kept from your grandchildren because your life is not as organized as it was before, because you are bed-bound, or because you cannot remember or recognize your visitors?  I suspect the answer is no.  You will want to see your family.

So you have the answer, do not keep the children from your parent just because they are not at their peak.  How much you included them depends on their age and capability. 

Small Children – No group provide more entertainment than small children and puppies.  Bring them along.  They will be of little assistance but will bring joy in abundance to your parent.
 
Grade school age Children -  This group will be most sensitive to an ailing parent and most concerned about mortality.  If they are not verbalizing their fears be assured that they are still thinking about your death or maybe their own.  It is a good idea to bring up your parent’s age.  It is also important to let them know that they will always be cared for. Bring them along and let them do chores that are age appropriate.  You can attempt to shield them though you will do so without success.  Part of growing up is developing an understanding of how the world works and your own mortality and that of your parents.  This group offers teaching opportunities.  Also, these are prime development years.  Watching you care for a parent is a wonderful example to set for your children.
 
Teenagers – Teens tend to be on and off again helpful.  These are the breaking away years and also the busy years.  If you can enlist their support for one or two consistent tasks such as shopping or grass cutting for your parent definitely hand over the task.
 
Adult Children – By the time your children are adults, you have hopefully raised them to help out.  They will likely be starting careers and families, and they will be very busy. Nevertheless, continue to request their assistance with whatever is reasonable. No task is inappropriate with this group.

I recommend that you base the task on the child's unique skills and interests.  Children can help with meal setup, teens with errands and yard work, while adult children can handle caregiving, sitting, or laundry to mention a few ideas.