Is it safe to say that it's all just Legosi's imagination? I mean, it's not like there's any information he didn't or shouldn't know in his dream. If it's really his mom's ghost or something, she would tell him her disdain against her komodo father even if it's implied, or at least that's what I would do. Like, "This is his fault, why does he have to be my father," or "I shouldn't have been born this way."