I'm not sure if it would be too complicated, but I think within the four stages of the peep lives ( Single 19-25, Married life 25-45, Midlife-Crisis 45-55, End of years 55-65) there could be some joy. Maybe once they hit an older age, 60 or so, one child would come to visit once a day for a real-time hour.

OR

You could have the 'next family' option automatically available after the Grandparents turn 65, at which point the child you choose would just move in with them. You'd need a guest bedroom in the house where the Grandparents would then sleep. There could be more actions added for the elderly, like rocking chairs on the porch, taking overly long naps, playing card games, knitting, etc. It would be so cute! They might not live much older than they would in VV (75 or so?) but it would add even more warmth to the game.