She died in Childhood when she was 7, she was betrothed to Raymond, the brother in law of John, she can survive to the same age as the OTL Eleanor of Provence or Isabella of Angouleme, however the territories of the Angevins need to be divided..and one of the daughters of John marries Louis VIII..
However Douce can be kidnapped by Henry II when he raided Toulouse..
Would the angevin empire still exist around this time, or rather could John having a son or sons who are slightly older and perhaps more competent change the outcome of his wars with Philip II?