Bertie's perspective, as revealed by the details in the passage, suggests that he is apprehensive about the implications of Florence's plans regarding Uncle Willoughby's manuscript. While the passage does not provide explicit details about his financial fears or the broader consequences of her demands, his tone indicates that he feels uneasy and is likely considering the impact of going along with her scheme. Therefore, the most fitting response to his perspective is:
He is afraid that, if he goes along with Florence’s plan, he will be financially cut off by Uncle Willoughby.