Is it permissible for another person to perform the Sa'y on behalf of a 'Umrah performer who is unable to do so, and is her 'Umrah valid thereby?

The rulings concerning deputization (إنابة) in performing Tawaf (definition) (circumambulation) and Sa'i (ritual brisk walking) vary depending on the condition of the one delegating. Deputization in Tawaf or Sa'i is not permissible for someone who is capable or whose ailment can be removed, or who can seek assistance from someone to carry them, because physical acts of worship are enjoined upon the Muslim to perform personally. However, deputization is permissible for someone who is completely unable to perform these acts or who suffers from a permanent illness that makes it exceedingly difficult to complete the rituals, provided that the cause of the inability is an illness from which recovery is not expected, and that performing Tawaf or Sa'i while being carried is not feasible for them.