Crook has a couple of different meanings, to “crook your finger” is to bend it, as if while pointing at someone—it is different than thumbs down. My assumption with the sentence you gave is that she is signaling for her husband to come toward her. It is really not commonly used in this way though, at least not in the USA! Crook is much more commonly used to mean thief, someone who steals, or someone who is untrustworthy. If someone was talking about a person and called them “crooked” it would mean they were not a good person, not to be trusted. However if they were talking about an object such as a line, or a road, or a painting on the wall and described it as “crooked” it would just mean that it was not straight.

Two different meanings in these examples 1. ‘Crooked her finger’ = bent her finger 2. ‘A crook’ = a thief