Thinking about all her life, or the last ten years exactly, Annabelle was now sure she would feel that something was wrong in her life if she didn't work, as she would have so much time on her hands and nothing to devote it to concerning her brother.
She needed to take care of her brother, but the way that had been ingrained in her was through providing for him. Now, if she couldn't work, she would have a lot of time on her hands, and when she had a lot of time, she would feel the need to take care of him. But all she knew was how to work. Annabelle found herself stuck in this never-ending loop, unsure of how to break free from it.
If she didn't work and provide for her brother's living expenses, then what else could she offer? Her reclusive brother wasn't sociable and preferred to stay in his room; she had never even heard him mention a friend.