Happier Than Ever (1984)

During the military dictatorship, a political militant takes his son out of the boarding school, and puts him temporarily in a friend's luxury and empty apartment in Copacabana beach. The son knows very little about his father, and the latter cannot really explain his activities to his son, fearing for his security. So the young man stands alone in the huge apartment, waiting for the infrequent meetings with his father, without really knowing what's going on.

Unfortunately the movie Happier Than Ever is not yet available on HBO Max.