"From the horror of 9/11, this was built to get goodness out into the world," says Bill Keegan, founder of HEART 9/11

Five days after Hurricane Maria devastated Puerto Rico in September of 2017, Bill Keegan, a retired lieutenant with the Port Authority Police of New York, and a band of New York City firemen, police officers and tradesmen from his nonprofit HEART 9/11 were there on the ground to help.

Soon after, actor Ramon Rodriguez, with family on the island, told Keegan he wanted to aid their efforts, and raised more than $500,000 for HEART 9/11’s work to replace missing roofs and rebuild entire homes for free.

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“When you see your island beat up, it’s heartbreaking,” the 39-year-old Affair actor — who worked with his “best pal,” actress Rosie Perez, on fund-raising — tells PEOPLE in this week’s issue, on newsstands Friday. “We just want to provide a solution. This is about helping human beings.”

With government efforts to fix the devastation of Maria slow and inadequate, an estimated 30,000 homes are still without roofs. Carmen Hernandez and her family, who live in the mountain town of Morovis, waited 15 long months living under government-issued blue tarps and with no electricity before her “angels” of HEART 9/11 rebuilt her home.

“I wish any family who lost a house to not lose faith,” she says. “HEART 9/11 is always where they’re needed.”

Image zoom Ramon Rodriguez and Carmen Hernandez Henry Hung

Since HEART 9/11 stepped in, first in underserved areas of the capital of San Juan before spreading out to the mountain towns of Morovis and Orocovis, where Rodriguez’s family lives, it’s replaced some 315 roofs and complete homes for free, with $2.5 million worth of construction materials.

While Puerto Rico escaped far more damage when Hurricane Dorian skirted the island Aug. 28, it remains in recovery. “It’s a tough thing to see two years later,” says Rodriguez. “There are so many homes that need work.”

For Keegan, 64, a night-operations commander at Ground Zero overseeing rescue and recovery following the Sept. 11, 2001 attacks on the World Trade Center, he yearned for this kind of work after retiring in 2005. He asked himself, “What do we do with this trauma and loss from 9/11?” and came up with the idea in 2007 of volunteer emergency-response work and HEART 9/11 (for Healing Emergency Aid Response Team).

HEART 9/11 volunteers, who have included some of Keegan’s former colleagues, have since rebuilt homes in Haiti after the 2010 earthquake there; counseled Newtown, Connecticut, first responders after the 2012 mass shooting at Sandy Hook Elementary School; and helped in the aftermath of floods in Texas and Louisiana.

RELATED VIDEO: Remembering Hurricane Maria

Since Hurricane Maria, Keegan has traveled to Puerto Rico from his New Jersey home so many times he’s lost count. Days after Hurricane Dorian made landfall in the Bahamas, Keegan was on a plane there with volunteers.

With an estimated 40,000 homes in Puerto Rico and the Bahamas still needing work, Keegan expects HEART 9/11 to be in both places indefinitely. The U.S. government promised the group funding, but it hasn’t come yet, says Keegan, who hopes private donations keep the work going. (To help go to heart911.org.)

Early on in their partnership, Rodriguez and Keegan came up with the idea of starting an apprentice program in Puerto Rico, in which HEART 9/11 volunteers train local residents in construction trades.

Maria Socorro Oyola, 47, was a rental car agent who didn’t know how to use a hammer before joining the apprentice program earlier this year. Now she’s a HEART 9/11 project manager. “People lose hope, and we say, ‘We are here to help,’ ” says Socorro Oyola.

Adds Keegan: “From the horror of 9/11, this was built to get goodness out into the world.”