The New Perspective comments on "planets moving closer to the sun?"

The thread is My boyfriend's roommate has a theory that the planets are moving closer to the sun and eventually Earth will become inhabitable and Mars will form life once it moves closer to the sun. Is this possible or no?According to theories and evidence presented here, this is definitely a possibility worthy of consideration.
"Inhabitable" means you can live there. So yes, Earth will remain inhabitable.

Mars will not become inhabitable because it doesn't have an atmosphere.

In about a billion years the Sun will start to expand, and the Earth will start to seriously overheat. At that point Mars will become warmer. However it will still not have an atmosphere, nor will it retain it if we could magically move lots of air there (or create air on Mars.)