Pelegrin Castillo, one of the architects of Article 37, says the constitutional ban does not prevent doctors from administering the treatment. It does, however, prevent them from practicing an abortion in order to treat the patient with chemotherapy.
Interesting - at the link above - the Doctors can go ahead with the chemo for the girl. It also states the family can decided. So something is a bit fluky here. If the family can decide and the Mother says 'start chemo' - then why have the doctors not done as instructed?
Sounds like some double-talk going on here. Obviously there's more to the story.