What Am I Riddles

Question: You are my brother, but I am not your brother. Who am I?

Question: If you throw me out of the window,
I'll leave a grieving wife.
Bring me back, but through a door,
You'll see someone giving life.

What am I?

Question: No matter how much rain comes down on it it won't get any wetter.

What is it?

Question: Many have heard me, but nobody has seen me, and I will not speak back until spoken to.What am I?

Question: I have Eighty-eight keys but cannot open a single door?

What am I?