Losing 35 pounds in three months is definitely worrisome. It needs to be evaluated further for chronic infectious diseases like Tuberculosis
or it might just be that he is not eating on time and healthy.
The other symptoms that he reports are all psychological; a psychiatric counseling will help him deal with these.
Please get his basic investigations done like blood count, urine routine and a chest x-ray. Your primary care
physician can help you better on this.
Overall, your son is fine. It is just that we need to find the cause for his weight loss
and manage him accordingly.
Hope this helps you.