Hi, I'd like to help you with your question.
It sounds like this little boy may need an evaluation either by his doctor or by a mental health professional. It is either one of two things- he has behavioral issues or he has a diagnosis such as autism, ADHD or another type of learning disability. The poor language skills may indicate a mild speech problem or be part of the autism diagnosis.
If there is a local children's hospital nearby, he could be seen there by a psychologist for the evaluation.
Behavior modification can also be used to try to temp his behavior. It sounds as if this has already been tried and it is not working so far. Until he has been seen and evaluated, it is unclear if the behavior modification would work. However, you can continue to try until more information is known about the reasons behind his behavior. Here is a link to help you with some information about techniques you can try:
I hope this has helped you,
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