The Wall Street actor was diagnosed with throat cancer in August (10), just months after 31-year-old Cameron was handed a five-year prison term on drug charges.
But Douglas is determined to support his son despite his own struggle with gruelling radiation and chemotherapy treatment - and regularly makes trips from his home in New York to Lewisburg Federal Prison Camp in Pennsylvania.
The father and son meet in the prison visitors' room in the grounds, according to official documents obtained by Britain's People newspaper.
Douglas' publicist Allen Burry says, "Michael is still visiting with Cameron. He is not going every day and not as often as he would like but he is still visiting with him."