The Action of the dying Sun

Why does the sun expand out as far as Jupiter before it contracts all
the way back to becoming a White Dwarf? Our sun would end up as a
neutron star if it had 50% more mass. A star with to much mass is not
beneficial for life. I don't think rock planets could form if their sun
only lasted for 100 million years. Lets go with that supermassive star
Eta Carinae it had a giant outburst,and released as much energy as a
supernova. This star is still around. Hmmmm How did it survive that
explosion? Astronomers estimate its mass to be 100 times that of the
sun. With that mass it should end up as a blackhole. It could be the
seed for another mini-bang that will reach a critical mass,and the
moment it stops spinning its horizon will collape into the core,and
release its singularity. to create a mirror image of the universe it
was recycled from.(I love that idea) Bert