I am experienced in writing of all kinds, including biographical memoirs and would be able to complete this project in a reasonable timeframe. English is my native language and as a Brisbane native, I'd be happy to meet with your father to better understand his life, and therefore portray it better. I'm sure that given more detail on how you'd like this project to be completed - word length, etc. - I'd be able to give you a more accurate time frame, but I think 30 days is a reasonable starting estimate.