This answer is a bit problematic. It directly accuses the person the OP is discussing as engaging in sexual harassment. This is terribly bigoted agains people with autism.
You wouldn't say that a deaf person is ignoring you because she can't hear you or a blind person is not paying attention because they cannot see, so why should it be acceptable
to say that a person who cannot read social cues, who is acting without malice, is engaging in sexual harassment? Not even the OP stated that.