Firestorm,

I am a newbie to this forum, but I will take a stab at analyzing this for you.

It has been my experience that dreams of water represent emotions and babies represent new beginnings or the birth of new ideas.  My first reaction upon reading your description was that the "baby" needed to be nurtured and cared for.

Since this is your sister's recurring dream, my guess is that there is something new in her life or about to enter her life that needs emotional care or emotional cleansing.

As for the people involved in the dream (you, two sisters, your son, and deceased father), do any of them face the ending of a difficult phase in their life and need emotional help moving forward?  In this recurring dream, are all these people always there, including the baby that lives only in water?  The baby could also represent a change in the relationship among the people involved in this dream and it pertains to your sister, since it is her recurring dream.  The water in this case could mean emotional cleansing or the need for emotional nurture for any or all of the parties involved.

These are just some of my initial thoughts, as the dream you described was short and vague.  In closing, I thought it was interesting that, in the dream (which is your sister's dream, not yours), you are the one who carried the baby to the water chamber, and in real life, you are the one passing along your sister's dream to get interpreted.

I hope this helps.

Cecile