Allah Ta'ala says: “Never pray for anyone of them who has died and do not stand at his grave. Verily, they have disbelieved in Allah and His Messenger and died whilst they were transgressors.” (Surah Taubah – Verse 84)
However, one may visit the family or send a simple message of condolence to the bereaved. One should be careful of the words used to express the condolences. Making Dua for forgiveness or for entry into paradise for a deceased non-Muslim is not permitted.
In another verse Allah Ta'ala says: “It is not proper for the Messenger and those who believe to seek forgiveness for the disbelievers though they may be relatives, after it has become clear to them that they are dwellers of the fire.(Surah Taubah – Verse 113)