Dream character telling people they are dreaming

i had this dream yesterday where nothing really special , i was mad because after doing something i made a girl character not exist so i made her come back idk how i just wanted her to and demanded it and she did she hugged me and she whispered in my ear " your mom doesn’t want us to be together" and she disappeared , she was wearing this beautiful red dress , i was really mad so i started hovering , then one of the characters in the dream who i was with started telling the other dream characters this is a dream this is all not real this is all imaginary . how did he do that ? why ?

Since the dream characters are just manifestation of your subconscious it would stand to reason that after making these changes in your dream you realized on a subconscious level that none of this could be real. So these manifestations began talking about this realization amongst themselves.