How are Florent and Quenu related?

Florent, the older of the two boys, is the product of his mother's first marriage. Florent's father was a very tender-hearted man from Provençe in the south of France, on the Mediterranean coast. Florent's mother lavishes most of her attention on him. Quenu's father is their mother's second husband and when Quenu is still a very young child (around two or three years of age), his father dies of indigestion.