Although Dave was often regarded as the fool in his friend group and frequently ended up looking like a clown, he was still one of the male leads and the young Minister of the country. His position wasn't achieved through connections or luck; he earned it through his own merit.
He was adept at negotiating with leaders from other countries and was often seen as a cunning strategist. As a result, understanding someone's thought process and intentions was second nature to him. This skill allowed him to accurately gauge what was going on in Alice's mind at that moment, and he had no hesitation in sharing his insights with the group.
This also indicates that in the novel 'The Thin Line Between Love and Lust', Dave is fully aware of Alice's scheming but chooses to ignore it, either because he is attracted to her or feels like they are the same kind of people. It suggests that he allowed her to act freely, observing as she manipulated his other friends while he played along.