Over the years we've been in a similar situation twice, and both times we've been kept ignorant -- which was the kindest thing, given the circumstances:
- We went to Florida (Seaworld actually, not Disney) for a short vacation, and my grandfather died suddenly on our last full day of vacation. My mother chose NOT to call us. As soon as we got home, she told us everything, and we had to hurry to prepare for the funeral, which was the very next day. However, by NOT telling us, we were able to enjoy our last full day of vacation and drive home with a calm mind. We could not have done anything to help my grandfather, and his funeral was pre-planned.
- We took our two nephews on a cruise. When we returned to the US, we called the boys' parents as soon as we disembarked, loaded the car, and made it to the interstate. Their parents told us that the boys' grandfather had died the day before, and they asked us not to tell them. What would have been the point? To make them cry in their last few hours with their cousins and be unhappy on the long drive home?
Sometimes ignorance is bliss. If you can do something, great -- go home -- but so often, your presence makes no real difference.