Is it permissible to say "may he rest in peace" for a deceased person who used to insult the Divine Being, commit blasphemy, and neither prayed nor fasted?

Whoever insults God and dies upon that without repentance, it is not permissible to invoke mercy upon him or seek forgiveness for him, because he is a disbeliever. This is confirmed by His (Allah's) saying: {It is not for the Prophet and those who have believed to ask forgiveness for polytheists, even if they were relatives, after it has become clear to them that they are companions of Hellfire}. The sin of the deceased does not harm you, for "no bearer of burdens will bear the burden of another," and the believer is content with God's judgment and submits to His command, and shows enmity towards those whom God has shown enmity towards.