Okay,
I think it is obvious why Dumbledore could die. He is old!
It
is normal for people to die as they age, and for Dumbledore, it
seems
like time is running out. Harry frequently observes the ancient
look
etched into Dumbledore's face,and Voldemort, though a weaker
wizard,
could do whatever it takes to take out the greatest sorcerer of
all
time.