Psychologically speaking, it should be that you have always had deep feelings for your brother. Something recently may have inadvertently aroused your subconscious memories of your brother, reflected in your dreams, and deepened this subconscious impression. No big deal. This phenomenon will be alleviated after the attention shift.
I suggest that you have time to visit the grave, and then chat with your brother before the grave and have a psychological talk. Talking about your parents' shortcomings will ease your mood.