It's most probably his grandson Josef Lada (*1960), who recently re-published some of Lada illustrations in new books.
However, you would have to examine the question of whether the copyright on a particular work of his expired 50 years after publication, 50 years after his death, or 70 years after death (which will be 2027).
Josef Maria Pernter has written: 'Methods of forecasting the weather' -- subject(s): Weather forecasting
Legally, the author of any work owns the copyright until they transfer it to others or it is transferred by law (such as inheritance).
The cast of Zwischenfall - 1999 includes: Petr Jelinek as Partisan Karel Knap as Soldier Libor Kozusnik as Soldier Josef Kubista as Soldier Patrick Pavel as Soldier Juri Rothenbuehler as Sergeant
The cast of Greenhorn - 2003 includes: Bettina Dorn as Daughter Kolja Kleinschmitt as Grandson Joachim Lautenbach as Soldier 1 Josef Quadflieg as Old Karl Stefan Rosmiarek as Soldier 2 Tim Williams as Sam
Josef Roden's birth name is Josef Rebec.
Josef Jarno's birth name is Josef Kohner.
Josef Dannegger's birth name is Josef Deutsch.
Josef Berne's birth name is Josef Berstein.
Josef Reithofer's birth name is Josef Kiesslich.
Josef Pfitzer goes by Josef Ludwig Pfitzer.
Josef Meinrad's birth name is Josef Moucka.
Josef Schaper's birth name is Josef Schapira.