In this autistic study from Yale University, researchers found that emotional activation by Digimon characters (at least as measured by the amygdala) was stronger than for familiar faces(controls were non-autistic liking Digimon and autistic with no interest in Digimon).
Problems emotionally responding to familiar and unfamiliar faces create significant social challenges. But like everything else involving the brain, functional differences may vary widely. Some people with fairly severe facial recognition problems can intuit emotions from other senses - including tone of voice or body gesture. Dissecting out the individual differences in recognition and emotional responsiveness will tell us more about amygdala functioning in autism spectrum disorders, and about what variations exist.
In the pictures below, the arrows point to the amygdala. The scans are from the autistic Digimon fan.
In this boy's case, it's even possible that his primary problem may be with visual perception of faces. There are some studies that have shown that some autistic subjects are better able to perceive facial expressions in caricature form than 'in real life' or in photographs. The reasons for this are not entirely clear, but it might be that photographs or 'real life' faces are presenting too much visual information that can be taken in at once. Think about how much memory it takes a computer to download a photograph compared to clip art.
This information can be important to know because some can be taught to improve their emotional facial recognition by either a part-to-whole method (start with only a part of the face like the eye brows or mouth, looking at the face bit-by-bit) or by training first with caricatures (less information), moving on to exaggerated black and white photographs, then finally real life.
Differences in Emotional Activation in Autism - Human Faces and Digimon