What is the ruling regarding my wife's missed fasts from last Ramadan due to breastfeeding and postpartum bleeding: Is she only required to offer expiation (kaffarah), or to make up the fasts, and when should she make them up, and is it permissible for her to make up the fasts after the current Ramadan?

If a wife breaks her fast due to postpartum bleeding (nifas (definition)), she only needs to make up the days (qada'). However, if she breaks her fast after becoming pure from nifas due to breastfeeding: if the concern is for herself, she only needs to make up the days; but if the concern is for her child, she must make up the days and feed one poor person for each day. In all cases, merely offering expiation (fidya) is not sufficient; making up the fasts (qada') is obligatory. If she delays making up the fasts until after the next Ramadan (definition) with a valid excuse, she only needs to make them up when she is able. If she delays without a valid excuse, she must feed one poor person for each day of delay, unless she was unaware of the impermissibility of delaying.