1,001. Drinking on Purim - But Not Too Much!
142:6 The Purim miracle was brought about through wine - Vashti was deposed during a banquet of wine, causing her to be replaced by Esther; Haman's downfall was likewise brought about through wine - therefore we are obligated to celebrate by drinking wine. The Talmud (Megillah 7b) says that a person is obligated to drink on Purim until he does not know the difference between "cursed be Haman" and "blessed be Mordechai." One should at least drink more than he usually does in commemoration of the Purim miracle, then fall asleep. While he is sleeping, he certainly won't know the difference between "cursed be Haman" and "blessed be Mordechai." (Mishnah Brurah 695:5 approves of this course of action.) One whose nature is weak, or who knows that if he overindulges he will likely come to treat some mitzvah, bracha or tefilla lightly, or one who knows he will behave inappropriately, should not drink so much. By not drinking, all of his actions will be considered for the sake of Heaven.
142:7 A mourner, even during the week of shiva, is obligated to give gifts to the poor and to send portions to his friends. He should not send something that is associated with joy. We do not, however, send gifts to a mourner the entire twelve months of his mourning period, not even something that is not associated with joy. (Twelve months is for a parents; it's 30 days for other relatives - MB 696:20.) If the mourner is needy, he may be given money or other things that are not associated with joy. (If he is needy, he may be given money even during the week of shiva - MB 696:19.) If there are no Jews in a particular place aside from the mourner and one other person, then he must send portions to the mourner in order to fulfill the mitzvah. Regarding an onen, see above, 141:21.