The sun going red giant is unlikely. However its energy going ultraviolent is possible. The sun is a ball of compressed gasses. So it cannot grow (because its own gravity is too massive to let most of the matter excape the solar disk).

What he should be saying is that the mixture of cosmic energy will allow larger coronal mass ejections to take place because the gaseous interactions of the solar matter and foreign gasses will respectively marry and become ultraviolent. This dealing blow after blow to the solar magnetosphere, and leading to various magmatic earth movments along the process.

The only way the sun would go red giant is during a fast paced supernova, in which the amount of gasses on the sun dwindeled, which significantly reduced its Mass, leading to an expansion of the surface area, and likely a super nova. (which will happen in roughly 600,000 million years) when the solar disk is in a critical state and dieing. (this is a known process in astronomy).