An important aspect of this that has been recognized in recent years is that of what has come to be called the "extended family."
That is, the concept that, in addition to the nuclear family (mom, dad, kids), other family members, such as grandparents, aunts and uncles, etc., are included in, and operate as part of, a now larger family, providing assistance and services that add to the good of everyone.
There are a great many web articles on this, this one being short but discussing the highlights of such an arrangement:
http://www.fourwinds10.com/siterun_data/spiritual/inspirational_general/news.php?q=1201389832Grandparent participation in such extended families is indeed pretty common. And it can be very positive. In my own case, I remember clearly when Grandma came to live with us when I was a young child. The fact of the matter, which of course I didn't know then, was that she was nearing the end of her days, and moving in with one of her children was her best option.
But while she was with us, her influence on me, with the wonderful stories she would tell me, watching me while my parents were at work, the
cookies she would bake, and things like that during that time, were very memorable experiences indeed. She lived in the guest room, and it was truly a sad that day when I came home from school to be told she had passed away that morning.
Some sociologists have argued that the decline of the extended family in the modern world has been one of the reasons for much of the difficulty that we currently face as a society. Possibly so, but it does seem a shame that many of the advantages of the extended family, such as are described in the above article, and as I know from personal experience, are lost when our nuclear families become isolated from other family members.