Children have American green cards, can parents immigrate to the United States?

No way! This is a civil right, not a green card.

But now the situation has changed, and Trump's parents' immigration application will soon be invalid.

The government doesn't need these parents to enjoy American welfare!

Now, if you want to enjoy the welfare of the country, you must find a job.

If you can't work, then your financial guarantor is in charge of everything for you, and the government won't care anymore.