PLEASE HELP, does my little brother have some kind of psychosis?

I really cant write this without crying, but my brother who is 11 has confessed to my mom for weeks now that in his head he is thinking very bad thoughts. He says in his head hes always saying "GD" and hes always crying to my mom about it because he doesn't mean it nor like it. And my family loves God very much. Were not like very religious or anything but God is in our hearts. I dont know what else he told my mom but my mom took him to his doctor and he wrote him a script for a psychiatrist. And well my mom, my friend and my brother pulled an all night and went to the beach today and on the way home he really freaked me and my friend out. He took a nap and went he woke up, maybe like 10 minutes later he started acting strange. He kept smiling at us and was getting mad the next. He kept telling my mom to speed up and hurry up. And went we got home, he told my mom hurry up get out of the car, hurry you hag. And I was just stunned...I just wanted to cry. Hes never acted this way before! My mom just started laughing, she kept trying to blow it off. And my friend and I knew something was wrong with him. And I kept telling my mom there is something wrong, hes scaring me. So when we got in the house and went upstairs, he went to go change in my dads room and I asked him if dad was home and he started to walk out slowly smiling and said "No, I killed him" sometimes he does joke around, its like an inside joke between us. But it just felt like he meant it. But afterwards he said, I'm just kidding. I told my mom and she just kep saying, hes just tired he hasnt slept and my dad said the same thing! And I just wanted to cry soo bad..but she said he isnt going to see a pyschiatrist. I just couldnt believe what I was hearing. I took a shower and I just broke down. I'm in my room now and I'm still crying. I just feel so depressed right now. Please someone help, tell me he will be alright. I prayed to God and I just hope he answers. Please, could he have schizophrenia?