At 50:33 into the film, a photograph using flash photography (note the brightness and deep shadows, even right at the back of the house interior) is stated to have been taken in 1865. Flash powder wasn't invented until 1887 and the so-called flash lamp wasn't invented until 1899.
At 52:50 into the film, the sister says that she knows that Victor is dead but the only fact that has been stated previously is that he disappeared about 2 years ago. There is nothing to say that he is dead.