The Sandbox

I found Edward Albee's "The Sandbox" interesting to say the least. The play is constructed like a play with voiced stage directions which is odd considering, in my experience, theatrical performances lean toward acting as "real life" rather than fictitious acting. I didn't know exactly why the characters "Mommy" and "Daddy" were named the way they were especially since it is not evident that they have children themselves. And why are they taking this poor woman out to the sandbox to die and be taken away by the melodious notes played by the musician and the muscley actor/angel of death? What is the purpose for the musician? Is he solely there to whisk Grandma away to her death? Why do Mommy and Daddy sit and wait an entire day and night for -what seems to be Mommy's mother - to die? Perhaps this is the story that is told to the children of Mommy and Daddy - to better ease their thoughts of Grandma dying. Really, I'm just confused about this play. I think there is a lot buried under the surface of this play and, if dissected, would probably reveal a lot of hidden tones and meanings hinting at life and death.