Jon's Aunt Janet was the one in the hospital. Aunt Janet was the twin sister of Jon's mom, Susan and was definately the more extroverted and adventurous of the two. Unlike some sets of twins Jon had met, his mother and aunt had no problems being twins, probably due to their personality differences, and, in fact, enjoyed it. According to the wish, she had gone into the hospital to undergo a special proceedure. Completely voluntary, it was some sort of transformation, though the transformations didn't always have to be physical.
The stone had conveniently made an 'extra' section of the hospital that Aunt Janet was in. Jon knew that, despite what the stone had told him, he would not be prepared for what he saw when they met his aunt.
