Is One Rewarded for Preparing the Dead for Burial?
Question

What are the rewards for preparing a dead body for burial?
Praise be to Allah.Shaykh Sa`d Al-Humayd (may Allah have mercy on him) said:
“We do not know of any authentic evidence to indicate the amount of reward earned by the one who prepares the deceased for burial, but the Bounty of Allah is vast.”
The one who prays (the funeral prayer) for the deceased will have one Qirat of reward (a Qirat is equivalent to the size of Mount Uhud), and the one who accompanies the funeral procession to the burial will have two Qirats . For the one who seeks reward by preparing the body we hope that there will be even more reward.” 
Shaykh `Abd Al-Karim Al-Khudayr (may Allah have mercy on him) said: 
“Washing the deceased is Fard Kifayah (i.e., a communal obligation, whereby if some members of the community undertake this duty, the rest are free from sin, but if no one does it, all will be sinful), so there is no specific reward. However, if sufficient people do the job, it becomes Sunnah for the rest. There are no reports which describe a specific reward, but there will be a reward for it because it is an obligatory duty, and not doing it is a sin.” 
For more details, please see the following answers: 12363 , 14040 , 14522 , and 35853 .
And Allah knows best.