Her eldest girl was likely, Captain Hannay thought, to take after her mother, whose pet she was, while Isobel took after her father.

He had suggested that both should be sent to school, but Mrs.Hannay would not hear of parting from Helena, but was willing enough that Isobel should be sent to a boarding school at her uncle's expense.
As the years went by, Helena grew up, as Mrs.Hannay proudly said, the image of what she herself had been at her age--tall and fair, indolent and selfish, fond of dress and gayety, discontented because their means would not permit them to indulge in either to the fullest extent.

There was nothing in common between her and her sister, who, when at home for the holidays, spent her time almost entirely with her brother, who received but slight attention from anyone else, his deformity being considered as a personal injury and affliction by his mother and elder sister.
"You could not care less for him," Isobel once said, in a fit of passion, "if he were a dog.

I don't think you notice him more, not one bit.

He wanders about the house without anybody to give a thought to him.