No don't send it, it has no positive outcome and you do not need to go to others levels.
I got a phone call off my childrens Nanna for the first time last week. Not heard from her in three years and she was dreadful to me when i was with her son. Won't go into that though or even drag it up as it is water under the bridge.
I am meeting her tomorrow, i said she could see her grandkids but i would stay so subsequently we are all going out for dinner. The reason i am going out and not complaining to her or asking her where she has been will cause more harm to me than anyone else. i will become angry and bitter. I'm just going to hear what she says, smile inanely and come home and drink.
Sod it all, you can never change other peoples behaviour and it is a waste of energy even trying. Even if you point out where they are going wrong all i think it achieves is a bigger bridge. You then start to wonder if you have caused all the problems. Keep your conscience clear.