I thought you wanted the point of when Cooper went into Gargantua.
Dr. Man is prior to that. Long story short, Dr. Man knew Dr. Brand was full of shyt with the whole Plan A & Plan B. When Dr. Man landed on the ice planet, he knew immediately that there's no way for restart mankind on this planet and now he's isolated by himself. That isolation made him mad and desperate to return to Earth. He pressed the beacon to single NASA back on Earth there's habitual life on his planet, but really so he can get them there so he can take their ship and ride out. Then he put himself to sleep until they eventually got there.
Dr. Man's part of the story addresses the larger part where Amelia and Cooper were debating which planet to go. That's where Amelia's theory of LOVE is an unexplained connection that cannot be quantifiable due to her feeling connected to her husband's planet without any rhyme or reason. Whereas Cooper, who been throughout the movie believes in hardcore science and mathematics over spirituality just looked at Amelia as being sprung and not thinking logically and argued that Dr. Man was claimed by Amelia's own admission to be "the best of us" and his beacon is making it loud and clear to come there, and the planet is closer, and the fuel situation. So, he overruled Amelia's preference to go to her husband's planet (even though Amelia ended up being correct).