As other comments and answers have pointed out, it would be very hard to find a way for any life to survive on the sun, even with a super material like that.
But lets see if we can alleviate some of the problems:
- The Sun Does Not Have A Solid Surface
This is only superficially difficult. We won't land on the surface - as there isn't one. We'll be traveling inside some ship or device that doesn't land. Like an airplane that flies in Earth's atmosphere and doesn't lands.
I can't think of a solution, except of adding one more super attribute to the super material: it absorbs or reflects most of the radiation.
28 g means that humans can't survive but we could convert our idea for the flying ship to a gigantic torus that its center is the same as the Sun's and rotates quickly enough to create 27 or 29 g. Humans live inside.
- Magnetic Field and
- Solar Flares
The gigantic torus is insulated for magnetic fields and can withstand very high temperatures from the outside.
- Food, oxygen, water and other things
Everything needed for survival is brought into the torus after it has been created, in vast quantities. The plan is to create a self-sustainable environment, with soil, plants and animals.
Conclusion: Not sure how feasible any of these ideas are. They seem quite ridiculous at first glance but the bigger obstacle is the existence of such a super material. If there was such a thing, it might be just possible to overcome the rest, although I don't see why it would be a good idea. If the technology was so advanced to make something that survived on (or in) the sun, it would certainly be easier to build spaceships-planets that go around the sun and not so near it.