Gathering in the house of the deceased and offering a collective du’aa’ for him
Question

                when some one dies...families go round to the deceased houses and sit with there families and make a collective dua..is this permissable?

and in the masjid they hold a 'khutam'...is this allowed?
Praise be to Allah.Among 
          the fatwas issued by the Standing Committee for Issuing Fatwas is the 
          following:
We 
          do not know of any evidence (daleel) from either the Qur’aan or Sunnah 
          to indicate that it is prescribed to recite any soorah of the Qur’aan 
          in any place, or in the house of the deceased. We do not know of anyone 
          among the Sahaabah or Taabi’een or Taabi’ee al-Taabi’een [i.e., the 
          first three generations of Islam] from whom it is reported that he did 
          that. The basic principle is that this is not allowed, because the Prophet 
           (peace and blessings of Allaah 
          be upon him) said: “Whoever does any action that is not in accordance 
          with this matter of ours [i.e., Islam], will have it rejected.” (Narrated 
          by Muslim, al-Aqdiyah, 3243). With regard to gathering and making 
          du’aa’ for him, du’aa’ is an act of worship, and acts of worship are 
          based on the principle of tawqeef [i.e., to be based solely on the saheeh 
          texts, with no room for adding or taking away anything]. It is not reported 
          that the Prophet  (peace and blessings 
          of Allaah be upon him) made du’aa’ with his companions for any deceased 
          person after he had completed the (funeral) prayer. It was reported 
          that he used to stand by the grave after the ground had been levelled 
          over its occupant and say, “Pray for forgiveness for your brother, for 
          he is being questioned now.” From the above we know that the correct 
          thing is not to offer a collective du’aa’ after offering the funeral 
          prayer, and that this is bid’ah. 
Fataawa 
          al-Lajnah al-Daa’imah, 9/16 
So 
          pray for your deceased each one of you individually. It is OK to make 
          du’aa’ for him during salaah and at other times, at the times when du’aa’s 
          are answered, such as the last third of the night, the last hour of 
          ‘Asr, Fridays, between the adhaan and ‘iqaamah, etc. You should be sincere 
          in your du’aa’. When the du’aa’ is only between you and Allaah, you 
          will feel more khushoo’ and will feel more sincere than when 
          you make du’aa’ simply to please others, as when people recite du’aa’ 
          collectively to please the family of the deceased. May Allaah help us 
          and you to do all that is good.