Hahahahahahahahahahaha
This is the kind of thing a 13-year-old who just learned about the existence of the Commonwealth would propose. I don't oppose joining the Commonwealth, but it accomplishes literally nothing because the Commonwealth is totally irrelevant and powerless (and the US might not even be welcomed). That said, reading the article, it's not a Trump administration proposal, just some random Brits.
This is factually correct.
The Commonwealth is utterly irrelevant, has absolutely no power or influence, and for most people from Commonwealth countries, the thing basically starts and ends with the fact that they organise the useless version of the Olympics.
The only people who ascribe any importance to it are the swivelled eye types who wish the empire still existed.