The basic weirdness thing you should know about this dream is it was of someone reading a book of this story. So all the while it's telling a story it's also reading that story from a book. Also think "Adam's Family" type setting.
Grandmother cursed rest of family because she thought they had become overwhelmed by material possessions and had lost love. The curse makes them immortal to the extent they can get parts of their body chopped off and still live. Blood wouldn't flow out of wounds and as soon as the part is reconnected they are whole again.
One day a stranger comes into their lives and starts changing everything. This stranger accepts them despite their curse.
Through time the stranger gets to know the entire family and each member (dad, son, mom, daughter) and all of their cryptic and horrific ways of living and being entertained (chopping limbs off eachother, scaring neighbors, playing pranks, etc)
Eventually the stranger is taken to a family crypt where a movie like scene takes place to show what happened back when the curse was first put on them. Each member is put into their own body of the scene and the girl would just watch, at first. Somehow the girl becomes involved in the retelling.
She visits the pond of two flies and a dragonfly who live happily in a little hermit type house. For some reason the two flies and dragonfly die, sadly.
The daughter finally meets the grandmother in-person at her trailer location with a picket fence. At that place there is a fly which speaks while the grandmother stirs a boiling cauldron of liquid. The stranger convinces the grandmother that the rest of the family have learned their lesson and to take the curse off. She does so.
The fly askes about the other flies and dragonfly on the pond to which he learns they are dead. Everyone goes to the pond again fully expectant to have a funeral when the fly turns around and looks at the stranger. "Do you think they can be brought back?" to which the stranger replies, "No. They're dead." The fly responds with, "You of all people here should know better." The fly closes his eyes. Soon the dead flies are lifted out of the water, blink back alive, and start flying around. Before the stranger can do anything the dragonfly is raised out of the water to repeat the same process. The grandmother smiles and winks at the stranger. "I told you."