After reading the thread up to this post, it sounds like the changes (especially pregnancy) may be the cause for this behavior. A child may feel like they are replaced and they may regress (or want to appear regressing) in areas such as potty training, dressing, feeding and for GT kids reading and writing. Since he is clearly still reading in secret, he may want that alone time with parents through reading. I would certainly spend time with him reading but also other types of play. If he feels her gets attention through other activities, he may resume reading by himself.
