Are my mother's six days of Shawwal fasting considered a make-up for the days she missed in Ramadan due to childbirth, or does she have to make up other days?

Whoever fasts the six days of Shawwal with the intention of supererogatory (nafl) fasting, it is not permissible for him to count them as make-up (qada'). The mother must repent for delaying the make-up fasting. She must also pay a fidyah (definition) (expiation) for each day she delayed until the entry of the next Ramadan (definition), if the delay was without a valid excuse. The amount of the fidyah is one mudd of food for each day. However, if the delay was due to a valid excuse such as pregnancy, breastfeeding when there is fear [for the baby's health], illness, or travel, then she only needs to make up the fasts and the fidyah is not obligatory.