It is something I have seen people do as they begin to work through their grief and they realize there is nothing more they can do for their own child.
That is the key thing: As long as your child is living, most if not all people are simply not capable of diverting one bit of energy to organize efforts for other people's children. Yes, they make friends in the ICU waiting room and on an informal basis talk and offer support in an informal, emotional, personal way perhaps to other parents in the same situation.
But the organized, structured efforts--research such as Gerry McCann did when he came to the United States alone and met with Attorney General Alberto Gonzales--that simply does not seem to happen and it is easy to understand why not.
The only exception I know is a family whose son was diagnosed with cancer in infancy, they began a Christmas gift program through their church when he was a toddler, for families with children also in that hospital system, with cancer patient children. When their child passed away on Dec. 31st they continued the program that following Christmas. It was more an extension of the informal support and personal relationships they had developed while spending hours in the waiting and treatment rooms.
My friend whose two year old dropped dead suddenly from an undiagnosed condition spent 5 years in Compassionate Friends before she spent the next 5 years as a facilitator for the group to help other parents.
Really, it is not that people are selfish or incapable of helping others while grieving or suffering.
It is the degree of intellectual and emotional energy needed to organize, research, and argue for support from other organizations. (I fundraise for the ballet, and there is a big difference between the individual and the corporate level of fundraising.
Kelly Jolkowski, mother of missing teen, Jason Jolkowski, is the organizer of Project Jason, a foundation devoted to the missing and changing laws about missing persons. However, it wasn't until 2003, two years after his disappearance, that the organization was founded. Kelly posts here at WS.
http://www.projectjason.org/