The 33-year-old arrived in Amsterdam on loan from Braga in January. The Brazilian stopper has since played more than expected as first goalkeeper Remko Pasveer dealt with lingering injury issues.
However, in an interview with De Telegraaf, Matheus shared a story of personal sorrow as he deals with a hard time behind the scenes.
"I'm going through a difficult time because my father has been diagnosed with cancer, and it's hard to deal with. People often see me with a smile but don't know what's happening behind the scenes. This is the moment to share it," said Matheus.
"Apart from my father's situation, my family and I are very happy in Amsterdam. Ajax are a great club, where I can realise my ambitions," added the Brazilian goalkeeper, who is happy with the move, despite what Braga wanted.
"Braga wanted to keep me, but I see this as a step forward, a good adventure."
Although he's excited about the challenge he's taken on in the Netherlands, the goalkeeper recalls adapting wasn't easy because of the Dutch weather.
"We arrived at the beginning of February, when it was minus four degrees here. A Brazilian feels really out of his comfort zone," he said.