Is there any benefit in having a large number of people to pray the funeral prayer?

Praise be to Allaah. 

It was reported in the hadeeth of Ibn ‘Abbaas that the Prophet
(peace and blessings of Allaah be upon him) said: “There is no Muslim
man who dies and forty men who do not associate anything with Allaah
pray the funeral prayer for him, but Allaah will accept their intercession
for him.” (Narrated by Muslim). Hence the scholars regarded it as mustahabb
to look for a mosque in which there is a large congregation to pray
for the deceased. The greater the number, the closer that is to goodness
and the more du’aa’ will be made.