The film is based on a book of the same title by Frank McCourt. It is an autobiographical account of his childhood in the Irish town of Limerick (although some of his contemporaries have questioned whether the family was really as poor as McCourt makes out). Angela was his mother's name, but I'm not certain about the "ashes". Perhaps a reference to the emptiness of his mother's life? Or possibly meaning that the book is all that remains of her?
Allen, his contemporaries haven't questioned whether or not he was as poor as he made out, they try to make out the social/economic situation wasn't as bad as he makes out but since most of them won't read the book in protest at what he has allegedly said I don't see how they could possibly question his recollections.