it is very difficult to reach a definitive diagnosis with the information that you have given about your 4 year old nephew but i will still hint at the possibilities. the first possibility to consider is that of disruptive behavioral disorder characterised by destructive and disobedient behaviors as in your nephew like hitting others yelling calling others stupid and missing school 4 out of 5 days. as children age oppositional and defiant behavior may continue and result in children having persisting conflicts with adults and peers at home and at school. the other likely possibility though is that of autism as indicated by stereotyped and repetitive motor mannerisms of opening and closing of hands plus the speech problems like inability to sustain a conversation delay in development of spoken language(as you said that his speech is hard to understand) preoccupation with stereotyped interest(as in going to bathroom on the porch). the other likely possibility is that of premorbid stage of childhood schizophrenia in the form of disorganized speech(before he can finish one talk he stops and talks about something different and completely unrelated) aggressive behaviour disruptive behaviour alternating moods inappropriate to environment school problems etc. the only thing missing is the presence of delusions and hallucinations which usually do not develop before mid adolescence. so it is difficult to commit schizophrenia but still suggestive of premorbid stage suggesting the likelihood of developing into full fledged schizophrenia in adolescent years of life. all above are the likely possibilities only as it is not possible to reach definitive diagnosis without detailed interview of child and parents and observation of the child in person. you must consult your pediatrician for the same as early intervention is always helpful in treating the psychopathology. hope this helps. take care.
my nephew who is four years has very bad mood swings and stops what he is doing and starts opening and closing of his hands. he tells his mother that he wants to break her bones and break the house. he goes to the bathroom on the porch and steps in ti and thinks it's funny. he is in time out at school 4 out of 5 days and the daycare provider said he needs to be seen by a doctor. my sister is so frustrated she doesn't know what to do. other things he does is spit at people hit others punches his mom yells a lot calls eveyone stupid says he wants to hurt animals and people. his speech is hard to understand. he starts a conversation and be fore he can finish he'll stop and talk about something completly different. my sister doesn't know what to do. she thinks possible autism. what do you think?