Reynaldo Leaños Jr. | KERA News

Reynaldo Leaños Jr.

Updated at 12:50 p.m. ET

Democratic presidential candidate Julián Castro knew he had to do something when he heard what was happening to LGBTQ and disabled asylum-seekers at the border.

To stem the flow of migrants across the southern border, the Trump administration is sending tens of thousands of asylum-seekers back to Mexico to await their day in U.S. immigration court — including some pregnant women.

It's back-to-school time on both sides of the U.S.-Mexico border, and in the border town of Matamoros, Mexico, migrant children are attending a different kind of classroom.

Volunteers have created a pop-up school on a downtown sidewalk in hopes of giving the kids some sense of stability.

"One, two, three, four ..." Tito, an asylum-seeker from Cuba, counts in Spanish in front of a group of children attending the sidewalk school recently.

He fled his native Cuba because he feared being persecuted for being gay, and he asked that we not use his last name.