Is it possible to be reassured that a person who died as a result of a bomb explosion while trying to protect his family, and who was of high morals and served people, is in Paradise?

No one can be definitively assigned to either Paradise or Hell except by a direct text (from the Quran or Sunnah (definition)). However, hope is held for the virtuous to enter Paradise, and fear is held for the wrongdoer to enter Hell. Based on the description of the deceased, it is hoped that he is among the people of Paradise, citing the hadith (definition) concerning praising the deceased, which necessitates Paradise, and the story of Harithah, who was killed on the Day of Badr, where the Prophet, peace and blessings be upon him, gave his mother the glad tidings that he was in the highest Firdaws (Paradise).