Offering condolence to the relatives of the deceased is traditional (Sunnat) act. Going for condolence within three days is desirable (Masnoon). But going to offer condolence after three days or a second time is undesirable (Makrooh). (Mala Budh)
While offering condolence, advising the relative to have patience, praising the good qualities of the deceased and also saying the following is desirable.
Allah says:-
Offering condolence is desirable (Mustahab) act, since Anhazrat Sal'am said, one who
persuades his brother to have patience in troubles, Allah rewards him with miraculous
robes on the day of Judgement. Offering condolence on the first day of demise is far
better than other days, because the feelings of separation from the deceased would be
greater and hence offering condolence at that time is appropriate. It is undesirable after
three days. But it is not undesirable after three days for a relative who is away and
comes after days for condolence. It is also undesirable at the door of the house. Offering
condolence at the grave is also
undesirable, because the grave is a place of invocation (Dua) and not for condolence.
Condolence should be offered in this manner, 'May Allah reward you more virtues,
patience and pardon your dead.' (Ghayatul Autar)
Bearing troubles patiently and saying 
is a traditional (Sunnat) act. Sending the
food for the deceased's family relatives on that day is also traditional (Sunnat). (Mala
budh)
It is a tradition in the holy group (Grohe-e-Mahdavia) that the spiritual guide (Murshid) sends the food to the family of the deceased on the first day and the other relatives send it for three days. It is preferrable that the relatives and neighbours should prepare food in such quantity that it may be sufficient for them to eat satisfactorily that day and night. In this regard the real base is the Hadees, that when the news of Hzt. Jaffer's (Raz). martydom was received, Hzt. Sal'am said, prepare food for the family of Jaffer (Raz.), they are in sorrow. (Fathul Qadeer)
It is hereby clarified that crying and lamenting loudly at the death, tearing clothes and beating the heads in sorrow is great sin and it is prohibited (Haram). (Mala Budh Mina)
Crying and wailing at the death of a person is a sign of open opposition to the Will of Allah and an expression of displeasure of Almighty Allah.
Allah says:-
(S57-A23)Do not be sorrowful on whatever has passed away.
Hadith Shareef:-
Hzt. ‘Omer Raz. has narrated from Hzt. Nabi Kareem Sal'am who said that “the
deceased is
tortured in the grave when any body cries loudly recalling and narrating over the grave.
Important:- If the dead had willed his relatives for weeping and beating it is permissible, otherwise not in view of this Aayat.
(S6- A146 ) No body shall carry the Burden of other.
On the other hand great Allah has promised to award great virtues to those who bear troubles patiently, so Allah says in Holy Quran in several place
(S2 - 153) In fact Allah is always with those who have patience."
Allah further says:-
(S8-A 46) "Have patience. Indeed Allah is with those who have patience."
Again Allah says:-
(S8 - A66 ) Allah is with those who have patience."
Allah says:-
(S-39-A10) "Those who tolerate very patiently will be rewarded countless virtues by
Allah."
Allah says:-
(S2-A153) "O’ people who have faith in Allah, seek help from Allah with patience
and prayer.
Indeed Allah helps those who perserve patiently."
At the time of death of any person, if tears come out of the eyes un-intentionally without any feelings of sorrow or grief, in obedience to the Will of Allah, such kind of shedding tears remembering one’s own death and sins committed for a long time, is good and useful.