Mushfiq Daniels, 28, was last seen on July 5 in Phu Nuan, Ho Chi Minh City, and his family have since travelled to the country in a desperate attempt to find him.
Thursday also marked two months since John Bothma, 22, from Gauteng, made contact with his family.
Santjie Dixon, who has been caring for Bothma since he was a minor, said no progress had been made in tracing him.
Daniels, from Surrey Estate, had been teaching in Vietnam since March last year, and it is believed he might have suffered a breakdown, causing him distress and disorientation.
His mother Faheema Daniels, his two brothers and relative Imaad Isaacs are in Vietnam searching for him.
They went to locations that Daniels had visited; spoke to locals, and visited various police stations yesterday.
Isaacs said the family had been in contact with the South African Embassy, which launched an investigation.
They had also been in touch with authorities since last week, but there was a miscommunication which they managed to resolve.
“Right now we are searching Ho Chi Minh City. We will likely get an update from the embassy in the morning,” Isaacs said.
Faheema Daniels said the family had faith they would find Mushfiq.
“We are keeping strong, keeping faith,” Daniels said.
A “Find Mushfiq - Ho Chi Minh City (HCMC)” page has been set up on Facebook for anyone with information on his whereabouts to get in contact with the family.
Department of International Relations and Co-operation spokesperson Lunga Ngqengelele did not respond to queries yesterday as he was out of the country.
He said he would do so when he had heard from his counterparts.
Meanwhile, Bothma was last seen on May 17 when he checked out of the Saigon Hub Hostel.
Dixon said Bothma was supposed to visit home on June 1 and they had booked and paid for his plane ticket.
Since his disappearance, Dixon said there had been a lot of speculation about his whereabouts, including rumours that he had left his passport at a hostel after he was not paid for work he had done.
“I was the last person he tried to call at around 8am. When I called him back his phone was off,” Dixon said, adding that she still felt her hands were tied.
“It’s as though someone has ripped something from inside of you.”