Zainal asked: What happens to non muslim’s who have drowned and died and body has never been found? what does the Quran say?
Okay, I couldn’t find anything that answers this question directly, so the best I can do is to cobble together the relevant information from the Qur’an and the hadith.
As I’ve talked about before, the hadith do specify that Muslims who drown at sea are understood to have had a Muslim burial, and that Muslims who drown in service to the Muslim navy are understood to have received a martyr’s burial. But neither the Qur’an nor the hadith pay very much attention to questions about sailors – presumably this is at least in part because at the time of the codification of the hadith in the early Middle Ages, the Muslim navy was easily the weaker half of the Muslim military.
So there’s nothing specific that I can find about non-Muslims lost at sea. However, in terms of the rites of burial in general, although burial is required in Islam, it isn’t understood to impart anything in particular to the one buried – there are specific prayers for the dead, but there are also hadith that recommend against reading the Qur’an over graves or excessive weeping, all suggesting that burial was understood as a service for the living, not the deceased. Similarly, Islam has no clear conception of the manner of burial affecting the dead – unlike, for example, Medieval Christianity (thus the Medieval traditions of burning heretics and of decapitating suicide victims – these actions were understood to actually affect the soul of the deceased). So although all Muslims deserve a Muslim burial, it’s not necessary for perform a particular kind of burial for that person to enter Paradise.
But again, this all applies to Muslims. As for the death of non-Muslims, I think it would depend in part on whether the person was a member of the ahl al-kitab (people of the Book), in particular if he/she was Jewish or Christian versus polytheist. The hadith discussing the death of non-Muslims all focus on the person’s status as a ‘believer’, where belief is defined as belief in the God of Abraham. The Prophet (peace be upon him) is remembered as saying that anyone who believed in the God of Abraham would enter Paradise, even if they did not witness to it publicly. On the other hand, there are hadith which make nonbelief (that is, not believing in the God of Abraham) the gravest sin.
As for people of the Book, there are passages in the Qur’an that suggest that they would be judged based on their own Scriptures. This idea is expanding in the hadith, which include stories of the End in which all peoples of the Book are judged by their peoples’ Prophet. These stories often imply that Muhammad (s’lm) will do more to intercede for his community, and so his community will be the largest in Paradise, but there is still an underlying assumption that some members of the other communities might enter Paradise, as well.
So that’s pretty much the best I can come up with – there is little evidence for Islam placing any emphasis on a body needing to be buried as significant for the person’s redemption, and for a non-Muslim, their status in the afterlife would depend both on their religious identity, as well as probably the kind of person they were.
 Alternatively there are also hadith that say the gravest sin is suicide. Most agree that the second gravest sin is killing a child.