Are the symptoms that the questioner's brother is experiencing—such as distance from God, imagining things that have not happened, talking to himself and laughing alone, drawing a cross and writing "the Creator" and "the accursed" next to it—considered symptoms of sorcery?

What has been mentioned about your brother, regarding his talking and laughing to himself and writing next to a cross, may indicate that he is unconscious. In this state, the pen is lifted from him. We advise that he be given ruqyah (Islamic exorcism). It is forbidden for a Muslim to draw a cross, as the Prophet (peace be upon him) prohibited crosses and ordered their alteration.