Estranged Father's Death Certificate

My father left me and my brother with my mother to live with another woman when I was very young. My parents were granted divorce expartee since my mother stopped going to the court. He remarried after the divorce. My cousin recently informed me that my father has passed away on 31st August this year. So, I have been asking for death certificate or any document to show he is no more. They haven't given me any documents. I called the hospital where he passed away and they said I needed signature and authorization from his new wife. She has refused to give me that. Please tell me what are my legal rights to get the death certificate of my father. Can i get the death certificate from a government body without his current wife's authorization? Can i authorize my mother, his ex wife, to pick up the documents on my behalf?