If a person is unable to smell, such as if a person experiences nasal congestion or suffers an olfactory disorder, he obviously cannot recite the Beracha over the spices during Habdala. The question arises, however, as to whether he may recite the Beracha on behalf of others for them to fulfill their obligation. This issue is subject to a debate among the Halachic authorities. The Shulhan Aruch (Orah Haim 266:5) writes that such a person may recite the Beracha on behalf of others, however, the Hid"a (Rav Haim Yosef David Azulai, 1724-1806) writes that the custom does not follow the Shulhan Aruch’s position in this regard. According to the accepted practice, one who is unable to smell fragrant spices should not recite the Beracha of "Besamim," even on behalf of somebody who is able to smell and needs to fulfill his obligation.
The Mishna Berura (Rav Yisrael Meir Kagan of Radin, 1839-1933) follows the Hid"a’s position, and this is, indeed, the Halacha. Therefore, if a person has a cold or for some other reason is unable to smell the "Besamim," he does not recite the Beracha, even on behalf of others.
