I found this question interesting and at first glance, impossible. However, I looked deeper into it to find that it is possible to prolong the life of the sun. According to Our Space, if we were able to find a way to split the suns’ helium back into hydrogen, we could prolong the life of our sun by a trillion years. I assume that we would be able to continue doing that for eternity, so long as humans are still alive.
While we do not have the technology now, we still have a few billion years to find a way to do what is mentioned above. With that, however, would it be worth the time, energy, money, and so on? Also, humans may find another planet to inhabit way before that type of technology is necessary. As mentioned in the article, only time will be able to give us these answers.
If you are interested, the article below further answers the question of prolonging the life of the sun.