Who is Rennie Burgess from The Lottery Rose and what is their importance?

Rennie Burgess is Georgie's mother. She is described as an alcoholic, who cares nothing for her son, and who would rather spend all of her time with her boyfriend, Steve. Steve beats Georgie, and although his mother sometimes apologizes and promises to be a better mother..... over time, Georgie learns her words are all lies.