Age plays a vital role here as far as how I'd approach the child about donating. If they were old enough to understand, I'd simply explain their sibling was very sick and their doing this could make them better. I'd go through the procedure with them in hopes that the more they were educated on what would happen, the less scary it would be for them.
If the child was too young to understand, I'd see if there way any possibility of the doctor performing the procedure would be able to make it painless. If that was a possibility I would likely spare them many details other than they had to go to the doctor with their sibling and that it would help make their brother or sister feel much healthier and happier again. While it might be wrong to force a child to do this or leave out details, some would too young to understand and others would be too scared to comply.
Either way, this event would save the life of my other child and their sibling. It would just have to be done.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.