There are consequences if one breaks the law.
There are laws against non-citizens entering the United States.
If one violates the law by entering the Unoited States illegally, one should expect to face unpleasant consequences, . . . most likely arrest and incarceration.
If an adult is incarcerated for breaking a law, he should expect to be separated from his children. (This is no different from any other incarceration for breaking other laws; children of bank robbers do not accompany their parents into jail.)
DonDiego advocates that if a law is on-the-books it should be enforced; if it not going to be enforced it should be taken off the books.
Others advocate that some laws should not be enforced; this path leads to social disorder. How does one know which laws can be violated and which laws cannnot, . . . or if/when the decision to enforce/not enforce may be changed?
President Obama chose not to enforce the law by not arresting those crossing the border illegally, and thus avoided the "difficulty" of separating parents from their children.
Thus, the number of "illegals" has risen significantly.
President Trump has chosen to enforce the law.
Congress can change the law if Congress chooses to do so.
DonDiego suggests the interested reader, if any, consider the question as to why certain elected officials do not want the Government to enforce laws against illegal entry into the United States.