The Law of Responsibility for Those Exempt from It

Question: In the Mishnah Berurah, section 298, sub-section 34, the Pri Megadim raises a doubt whether a blind person can fulfill the obligation for others in the blessing over the fire due to the law of responsibility, or since he is exempt himself, he cannot. I would like to ask: what is the reasoning that, even though he is exempt, he can fulfill the obligation for others? After all, although we hold according to Rabbi Akiva Eiger, sub-section 5, that a woman is included in the law of responsibility, we also hold at the beginning of section 186 that if a woman is obligated in the grace after meals only rabbinically, she cannot fulfill the obligation for a man. Furthermore, if someone who is exempt can fulfill the obligation for others due to the law of responsibility, can a woman fulfill the obligation for a man in the blessing over the lulav and shofar, for example? Thank you in advance.

Hello Rabbi

The question is correct.

In later authorities, it appears that there is an opinion that a blind person is obligated in the blessing 'Borei Me'orei Ha'esh', because he benefits from others seeing and being able to assist him, as it is said that therefore a blind person blesses 'Yotzer HaMe'orot'.

However, the law is ruled that a blind person is exempt, because it is not enough that he benefits from the existence of light, but he needs 'until he is illuminated by its light' - to be himself part of the light. But apparently, the Pri Megadim included this opinion in the question of whether he can fulfill the obligation for others.

Rabbi Akiva Eiger, Orach Chaim, Siman 297, Seif 5 - regarding the blessing on fragrance.
In my opinion, even if it is a blessing of the commandments, since he has no sense of smell, he is completely exempt from this commandment and is considered not obligated in it, which does not exempt others, and it is similar to what will be below in Siman 589.

See also Shut Radbaz, part 6, Siman 2001