i'd say he does know her well enough, they have discussed her "problem" before, and the look on her face showed that she was immediately concerned..
as a guy, my concern is that her iq is so low that she even suggested such a game when she knew the possible outcomes.. that's a game for singles, not for ppl in a relationship. by her choosing a game like that, she just justified me pursuing Eva and Victoria on the side. it shows that she doesnt mind doing things with others.
but yeah, not a bad story so far. a bit of a slow burn, but the plot is believable enough to be taken seriously