Closing the Border according to Kushner was just a pressure tactic to get Congress to change the immigration laws,so much for shutting the Border down,all The squish advisors President Trump is listening to are not giving him good advice.
Making statements and then backing off,recipe for losing
Never make a threat to children unless you intend to carry it out. Considering the congress(both parties), Mexico and the central American countries all behave like petulant children, the threat has to be carried out.
Close the border and let no one in. Increase the transfer taxes on funds going out of the US into any Mexican/Central/South American financial institutions to pay for the cost of this mess they helped create on our southern border. Take the US Chamber of Commerce to task and their Republican lackeys as well.
I would also consider approaching the Texas governor about him asking the President to invoke Article IV Section 4 of the Constitution and deploy the US military and take aggressive action against Mexico. Pour US troops into Northern Mexico and stop the invasion. Arrest any central American they find trying to cross the border, place them on ships and haul their asses back where they came from in wholesale lots. The Mexicans will be pissed but at this point to hell with them, they are helping create this mess.