Amina Inloes, Amina Inloes is originally from the US and has a PhD in Islamic Studies from the University of Exeter on Shi'a hadith. She is the program leader for the MA Islamic Studies program at the... Answered 3 years ago

The soul will continue on its journey to the next phase of its existence, whether or not the body is buried. If it were necessary for a body to be buried in order for the soul to progress, the earth would be packed with lost souls since so many people throughout time have died and have not had burials!

However, it is likely that performing the appropriate funeral rites may ease the transition into the next phase of existence. 

If you are concerned about someone's soul, you could pray for it.