Is it permissible to pray over the deceased in his home before praying over him in the mosque, and is it permissible to pray over him before washing him?

Originally, it is permissible to pray over the deceased in their home.

Some scholars are of the view that it is not prescribed to repeat the funeral prayer over the deceased, whether in the mosque or elsewhere. Others see no harm in repeating it for someone who did not pray over the deceased the first time.

Purifying the deceased by ghusl or tayammum is a condition for the validity of the prayer over them, and the prayer is not sufficient if performed before purification.