Chris Brann can only cling to photos -- fleeting moments he's shared with his son Nico.

In just a few hours, whether he can ever see him again is on the line.

"This is the tipping point in this case, ultimately," Brann said.

Related: Brazilian couple indicted for helping daughter take son

Wednesday morning his ex in-laws, Nico's Brazilian grandparents, Carlos and Jemima Guimaraes, will face a federal judge in Houston. Their high-profile defense attorneys, Rusty Hardin and Jimmy Ardoin, will try to convince a judge to grant bail at a critical hearing.

"If they're given bond and leave that courtroom, they would never show up again, and my relationship with my son would be severed indefinitely," Brann said.

The Guimaraes have been locked up for several weeks. The FBI arrested them after their flight from Brazil landed in Miami. They're facing international kidnapping and conspiracy charges for helping their daughter, Marcelle, Brann's ex-wife, take the child to Brazil only to never return.

"International parental abduction is child abuse," Brann said. "My child has been through emotional trauma perpetrated by those two individuals."

Brann says the Guimaraes have unlimited financial resources and has no doubt they would run. And to make matters even more dire, his Brazilian attorneys have told him if he were to fly to Brazil again to see his son, he would be arrested by authorities there for allegedly owing child support in Brazil.

So Wednesday, the stakes could not be higher.

"Ultimately my son's ability to come home will be determined by whether they get bail," Brann said. "But hopefully tomorrow, we'll be one step closer to getting my son back."