() A family is frantically searching for two grandparents who were swept away in Texas floods and they’re not giving up despite “no sign of hope” thus far.

Ryan Brake, the grandson of missing couple Robert and Joni Brake, joined “Elizabeth Vargas Reports” on Monday to discuss the search after flash floods destroyed the cabin where Robert and Joni, both in their 60s, were staying.

“We have not heard anything, no updates,” Brake told . “We have spent a tireless amount of hours walking throughout the river. I know my dad  still currently  has walked about 18 miles through the river today, searching, but as of now, we have no update and no sign of hope.”

Brake’s grandparents were in central Texas visiting his uncle during the devastating floods. As the water began to rise, Brake’s father was able to reach Robert and Joni by phone and warned them to seek higher ground. The family is unsure if they were able to get to safety.

“They were both physically active and physically capable, but with the amount of water and pressure, I don’t know if anyone would have been able to move,” Brake said.

Brake’s uncle and his wife were able to escape their RV before floodwaters swept it away.