Summary[]
In Chapter 532 of The God of High School, the Sun expands at an abnormal rate reaching all the way to Mercury. This seems it may be due to Mori and Mubong going all out. I will be calculating the new GBE of the GoH's Sun.
Calculations[]
Some things first, we need to find the size and mass of the new sun.
For the size it is simple old suns radius + distance between Mercury for the new radius. The average distance between the Sun and Mercury is 58 million km (58000000000 m). The Sun's radius is 696,340 km (696340000 m).
58000000000 + 696340000= 58696340000 m Radius
For the full size, just times two
58696340000 x 2= 117392680000 m Diameter
Sun's Mass = 1.989e+30 kg
New Mass = (New Sun's Size/Initial Sun's Size)^3*Sun's Mass
(117392680000/1392700000)^3*1.989e+30 = 1.1912012e+36 kg____________
GBE[]
For this I will be using the cited GBE formula for stars on the wiki.
U= (3*Gravitational Constant*(Mass of object in Kg^2))/(r(5-n))
(3*6.67408x10^-11*(1.1912012e+36^2))/(58696340000(5-3))= 2.4201478e+51 J (4-B Solar System)
Conclusion[]
The new GBE results for the sun are:
2.4201478e+51 J (4-B Solar System)
Essentially, anyone destroying the sun in GoH (Post chapter 532) will be performing a Solar System level feat. Does this scale to anyone, I don't think so, although the Sun's expansion happened when Mori and Mubong went all out, maybe they would if you attribute this to them.
NOTE: The scaling part here isn't important, just if the calc is mathematically correct.