[The ruling on a woman who entered iḥrām for ʿUmrah but was too weak to complete it]

Answer: There is no objection to deputizing (appointing a proxy) for that where there is an excuse. Accordingly, the ʿUmrah is complete and valid, and she is not obliged to remain in Makkah until the crowds of pilgrims and ʿumrah performers abate if that would entail hardship for her and her company—“Allah intends for you ease and does not intend for you hardship.” [al-Baqarah:185]; “He has not placed upon you in the religion any hardship.” [al-Ḥajj:78]. If, however, delaying ṭawāf and saʿy until the crowding eases would not entail hardship or difficulty for her or her companions, then she must wait until she is able to perform ṭawāf and saʿy, in light of His saying, Exalted is He: “And complete the Ḥajj and ʿUmrah for Allah.” [al-Baqarah:196]. Similarly, if she is able—without unduly affecting her provisions—to pay the fee for someone to carry her for ṭawāf, then that is obligatory upon her in view of the verse just cited.
The same applies to Ṭawāf al-Wadāʿ: she may appoint a proxy to perform it on her behalf due to an excuse other than menstruation and postnatal bleeding; as for those two, Ṭawāf al-Wadāʿ falls away from them, and such is established by authentic Sunnah.
The evidence for what we have stated regarding the validity of deputization for an excuse is that it is established that deputization in Ḥajj and ʿUmrah is valid; it follows that deputization in their components is valid as well. The scholars of the madhhab, however, said—as in the marginalia on Sharḥ al-Azhār—that deputization is only [permitted] for the stoning and the nights of Minā and the night of Muzdalifah, because these rites are time-bound: whoever fears missing them deputizes due to the excuse; as for the other rites, there is no deputization because they are not time-bound in a way that one fears missing them. End.
The preferable view is what we have stated, for the evidences mentioned above.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.1