Well, it might be for a variety of reasons. Maybe the character's personality or actions made the zombie develop an unexpected connection. Or it could be a part of a strange and imaginative world-building in the comic.
Hard to say exactly. It could be that the author wanted to create a very unconventional and attention-grabbing storyline. Maybe there's some hidden trait or event that made the zombie have these feelings. It's all up to the creativity of the comic creator.
It could be a unique plot twist. Maybe the zombie saw something special in the character that attracted it.