What role does Diego, Olive's cousin, play in her life as noted in the novel, The Unhoneymooners?

Olive describes Diego as, "Twenty-eight, gay, and better groomed than I could ever manage..." (11). He is more than just a cousin to Olive, he is a close and supportive friend. When Olive doesn't feel able to talk to her sister about certain issues, she turns to Diego for advice or just amusing commentary.