Complex sentence: One of the main male figures in Vernon's life is his Uncle Sydney, Myra's brother who is a self-made man who runs a manufacturing business in Birmingham and is someone with whom Vernon instinctively feels uncomfortable.
Split into simpler sentences: One of the main male figures in Vernon's life is his Uncle Sydney, Myra's brother. He is a self-made man who runs a manufacturing business in Birmingham and is someone with whom Vernon instinctively feels uncomfortable.