How should I be kind to my atheist father?

Allah, The Exalted, has decreed that we be kind to our parents, even if they are polytheists, by honoring and obeying them in all that isn`t sinful, so that they might love Islam and embrace it as a result.

Is it permissible for a woman who broke fasting due to delivery to pay a ransom ?

She should make up for the missed fasting days once she becomes ritually pure, but it is impermissible for her to pay a ransom while being able to fast.

Is it permissible for one to give the Zakah(obligatory charity) to his indebted brother?

It is permissible for one to give the Zakah to his indebted , or poor brother.

For passing time, my friends and I have called a famous diviner. She told me that somebody had cast a spill on me not to get married for the rest of my life. I didn`t believe her, but I can`t forget her words. How can I protect myself from such thing?

Praise be to Allah the Lord of the Worlds.

Dealing with diviners is forbidden and what you are suffering from is due to your having consulted that diviner. Have trust in Allah and ask Him for forgiveness, but rest assured that whatever Allah has decreed will take place. And Allah The Almighty Knows Best.