Matthew, who is best known for playing drug dealer Terry Clark in the second series of Australian crime drama Underbelly, admitted himself into a private Melbourne hospital that specialises in drug and alcohol addiction earlier this month.
TV presenter Bert told The Daily Telegraph: "There is nothing to hide. We are with him and we hope for the best, and I have got a feeling that is going to be what happens.
"He is our son, we love him. It just happens he is also a very talented young boy. At the appropriate time, of his choosing, Matthew will talk about it."
Matthew is believed to be engaged to Transformers actress Rachael Taylor.