Have there been any documents or websites relating family members dying on the same day and at the same age?

Answer 1

Here's a couple

http://www.rense.com/general37/twins.htm

http://news.webindia123.com/news/showdetails.asp?id=162661&cat=India

This one is a little different, but kind of weird. two brothers died the same way 12 years apart.
http://news.bbc.co.uk/2/hi/uk_news/england/staffordshire/5342816.stm

I don't know unless they are twins how they could die the same day and be the same age as eachother unless you are talking about cousins and such.