Grandmothers are the source of all the family secrets. The decision is which to tell, which to write down & which to smother for a hundred years. Grandmother is free to tell any & all stories, true & false, about anyone who is dead, or past 75 & deaf.
These stories include the family drunks, why the aunt discovered three husbands, the village scatterbrain & the bad apple on the apple tree. The grand children will be wide-eyed. Your own children will not mind as long as you stick to your generation.
You’re safe writing down the family tree, making charts & graphs, supplying copies to all. Historical preservation is big these days, the father back the better. A definite service.
What grandmothers can do is to chart the family medical history. This will be much appreciated , since genetic factors are considered by doctors, e.g. diabetes, heart disease, allergies, twins & etc.
Generally speaking, your own children will not tolerate you telling tales about them to their own children. (A definite lack of humor in this area.) Be sure to write it all down, relish a little revenge,
Some times I don’t have to say anything. I just look smug when the dear father is urging his child to eat karela until he says, “Alright, ma, you don’t have to say anything.” Who said anything? He knows & I know. The bitter stuff never passed his lips.
I get what quite satisfaction I can watching him try to cope with his uncooperative little creature, after all he put me through in front of the in-laws.
It is a mistake to say your grown married son in front of his lazy child, ”Well, you just lay there on your back & watched television for three years when you were his age.” No way.