Dead kid was like 5 days old. Means he probably had health problems and likely didnt even make it home from the hospital. His sibling looks pretty young there, probably young enough that he was shielded from most of this happening. Probably didnt even really get a chance to meet/connect, much less "play" with his sibling.

Now mommy, who is distraught, rightfully so, over the loss of her child is forcing other child who had little to no connection to dead baby to come to a grave to play in a sandbox. That kid is scarred for life.

You should shelter your children from some things. Despite your grief.