I can only speak from my own experiences, but it's not helpful in the least. Let's pretend for a moment that he isn't being dicked around. Call me crazy, but I've only rarely been manipulated or had mind-games played with me. I think a lot of what we see as mind games is really just when what we interpret (or even hope for) isn't reflected in reality. If she was never showing him more than a normal level of affection, but he came to the wrong conclusion (as he seems to have) it's not a mind game, it's just being wrong.
So, let's pretend she isn't actively trying to jerk him around. What does he gain from the asking? If she already likes him, all it could do is push her away. If she doesn't like him, all he learns is that she doesn't like him. He won't learn anything about girls in general (or, if he does, it'll be an example of a posteriori logic gone wrong). I've known a lot of girls, and the only solid conclusion I've arrived at is that no two have similar diagnostic criteria for whether they "like" someone (unless they're very obvious about it).