Assuming that the Universe is expanding, the aliens are expanding with it.
Assuming that the Universe is 14 billion years old, then any event that is expected to happen in 100 billion years is nothing but pure speculation, designed to get people to read articles.
If the Universe is expanding like the article implies, then eventually, after a very long time, a few trillion years, perhaps, Mars will be so far from Earth that we will not see the light from it.
Frankly, my dear, I don’t give a damn.
In approximately 4 billion years, give or take a few hundred million or so, Sol will become a Red Giant, expanding out in size to the orbit of Mars, engulfing everything within that sphere in just a matter of days, burning it ALL to dust and ash................