[1] {Brachot 17b}
MISHNAH:ONE WHOSE DEAD [RELATIVE] LIES BEFORE HIMIS EXEMPT FROM THE RECITAL OF THE SHEMA' AND FROM THE TEFILLAH AND FROM TEFILLIN AND FROM ALL THE COMMANDMENTS MENTIONED IN THE TORAH.
Gemara: "{If the dead body} lies before him" - yes. Implying that if it does not lie before him - no.
And I'll pose a contradiction {from Moed Katan 23b}:
One whose dead body lies before him eats in another house. If he has no other house, then he eats in his friend's house. If he has no friend's house, he erects a partition and eats. If he has nothing with which to make a partition, he turns away his face and eats. And he does not recline {while eating} nor does he eat meat nor drink wine, and he does not mevarech, nor mezamen, nor do others mervarchin upon him nor do others mezamnin upon him.
Not mevarech -- to explain, the blessing of Hamotzi.
Not mezamen -- to bentch.
They are not mevarchin upon him -- that you should not say that it is he who does not say Hamotzi, but others eat with him and they bless Hamotzi and bentch, and he would fulfill via hearing. Therefore it informs us that he does not need.
Rashi explains: He does not need to bless the bracha of Hamotzi.
Which implies that if he wanted to bless, he is allowed. And that is not implied so in our sugya, for it is stated that here, outside four cubits, it is also forbidden. Thus, he is not able to bless.
And there are those who say that this that it implies that it is forbidden to bless is where he needs to engage in a need of the needs of the deceased, but if he already so engaged, or if there are others to engage, he is permitted to bless.
And in the Yerushalmi it is not implied so, for we learn there: He does not eat all he needs, and he does not eat meat, and he does not drink wine, and he does not bless. And if he blessed, they do not answer after him Amen. And others who blessed, he does not answer after them Amen.
And {meanwhile} in answering Amen he is not taken away from attending to the deceased, and even so it is forbidden.
And further, we say later on in our perek (daf 19): If the corpse is not there before him, they sit and read and he sits and is silent; they stand and pray and he stands and justifies upon himself the din.
And he does not engage in the needs of the deceased, from that which it states "he sits and is silent", and he is able to focus on the first pasuk. Therefore, it appears that anyone upon whom the aveilut is cast is forbidden to pray. And so is implied in the Yerushalmi in our perek.
For we learn there: They learnt {in a brayta}: If he wants to be stringent upon himself, they do not listen to him. Why? Because of honor for the deceased or because he does not have one to bear his burden? What is the practical distinction {between these two reasons}? When there is one to bear his burden. If you say that it is because of the honor of the deceased, it is forbidden. And if you say because he does not have one to bear his burden, behold that he does have someone to bear his burden.
But they learnt {continues the Yerushalmi}: "He is exempt from shaking the lulav!" Explain it as during the weekday.
But they learnt: "He is exempt from the blowing the shofar!" Could you say that this is during the weekday and not during Yom Tov? {Thus, it must be because of honor and not because of his burdens.}
Rabbi Chanina said: Since he has obligations towards it, [to wait for nightfall] to bring a coffin and shrouds for him (as we learn there, taninan, in Shabbat daf 151a, that we wait for nightfall at the Shabbat techum, etc., to bring him a coffin and shrouds), if is like he is carrying his burden.
And it is not that the Yerushalmi maintains that aninut is practiced on Shabbat, for behold in the Yerushalmi, it is stated "where are these words stated? During the weekday, but during Shabbat, he reclines {/makes a meal} and eats all his needs, etc." Rather, it brings a proof from that of Shabbat, and kal vachomer to Yom Tov, that it is permitted to engage in it in speech and to violate upon it a shevus {derabbanan}. Therefore, on Yom Tov, where it is permitted to bury him via non-Jews, and he is also able to engage with them and to wait for dark at the techum, we call him 'bearing his burden', and all the laws of aninut apply to him. But on Shabbat, since they do not bury him on Shabbat, even though it is permitted to wait for dark for him [the deceased], he [the mourner] does not practice aninut.
And there are those who say that whether for Shabbat or Yom Yov, aninut is not practiced in it, except for close to evening, since he is able to wait for dark at the techum. And this that he is exempt from blowing the shofar is dealing with where he did not have a shofar in the morning and he obtained one in the evening.
And so did they say regarding the Rambam za'l (that his sons died) [that his deceased was before him] on the first day of Rosh Hashana, and he commanded that they blow before him the shofar to fulfill for him the requirement.