This is utter rubbish, I'm not saying I agree with the US but they have been trying to acquire Greenland as far back as 1867 and successive administrations have tried but Trump has pushed it more due to increasing focus on China and it's purely due to security reasons.
Claiming it's because of his rich friends is just absolute rubbish, you don't need to believe everything you see online because you don't like Trump.
And this wouldn't be the first time the US has bought territory from Denmark, they bought the US Virgin Islands from Denmark, bought Alaska from Russia etc.
"But while American expansionism has regained steam under Trump, the idea of the US controlling the self-governing Danish territory long predates the current president.
US interest in Greenland dates back to the 19th century, when then-Secretary of State William H. Seward, fresh off the purchase of Alaska from the Russians in 1867, floated the idea of buying Greenland and Iceland from Denmark.
While the sale never materialized, the US continued to eye the world’s largest island at multiple moments throughout history, at one point discussing a possible swap with Denmark for US territory in the Philippines.
In 1946, following World War II, during which the US took over the defense of Greenland, President Harry Truman offered Denmark $100 million in gold for the island, though Denmark rejected the bid."