I was extremely angry with my father and took an oath that when he dies I will not attend his Janaazah.

Answer

You acted like a shaitaan by taking the haraam oath. When your father dies, then participate in the Janaazah, and pay the Kaffaarah of the violated oath. Right now you should repent and recite Istighfaar for your shaitaaniyat. If your father is aware of your shaitaaniyat, go up to him and profusely seek forgiveness from him. Paying the penalty for the violated oath is not sufficient. Furthermore, the Kaffaarah can be paid only on the death of your father, not now.