I know that somewhere in something I have read there is a comment that someone (Yaakov avinu?) was so spiritually pure/holy that his soul did not cling to the earthly shell that was his body but came ...
As far as I know, living people can positively affect the dead. This is the reason we say Kaddish and learn Mishnayos for the souls of the deceased. (Feel free to comment with more examples of this.) ...