Is it permissible for a Muslim to grieve over the death of a Christian because he will enter Hellfire after his death?

It is permissible to grieve over a disbeliever if they die not upon the religion of Allah, provided that it stems from human compassion, such as grieving for relatives or for someone who performed charitable deeds and possessed good character. The one who grieves in this manner is not to be blamed, just as the Prophet, peace and blessings be upon him, grieved for his mother and wept over her, and just as he grieved for his uncle Abu Talib. However, if the grief contradicts disavowal of the polytheists, or involves minimizing their disbelief, or believing that their good deeds intercede for their disbelief, then this grief is forbidden.