I agree with that. First, the Earth will freeze, and then the Sun will become so large that it will simply absorb the Earth (or, more precisely, when the star is close enough, the Earth will evaporate). However, due to the decrease in the Sun's mass (which loses 4 million tons per second), the Earth's orbit will increase, but it is not certain that it will increase faster than the size of the star. But even now, scientists with their supercomputers cannot say for sure what will happen in "several billion years."
http://www.astrogalaxy.ru/277.html, the fourth point, but I definitely greatly exaggerated about 30 years. At the moment, this is indeed not feasible, but, in my opinion, it is not nonsense and certainly not idiocy.
P.S. Physicist... He understands physics, but judging by all, he is as far from astrophysics as he is from Alpha Centauri now...