i'm a newbie here, but no stranger to odd scarey dreams, like the death omen dreams i had when i was a teen....all i remembered was sitting up, sweating,screaming...and finding out within 3 days i had lost a grandparent...all my grandparents died when i was in my teens...since then dreams have become a near obsession with me...i've kept dream journals for many years...they still amaze me with their messages....
Was your grandfather ill before he died? Sitting up screaming sounds like it could have been night terrors.