Is it permissible to offer expiation (kaffarah) for a vow to slaughter a sheep every year for life—a vow which has become financially unbearable—by performing the expiation for breaking an oath (kaffarat yameen)?

If your friend's inability to fulfill her vow persists, she must offer an expiation for a broken oath (kaffarat yamin). However, if she hopes for her inability to cease, she should wait to fulfill her vow, and there is no expiation required for the period of inability. The Shafi'is and Hanbalis have held that whoever vows an act of obedience and then becomes unable to perform it due to an inability that is not expected to cease, must offer an expiation for a broken oath.