Hello! Thank you for asking on HCM! I read your question carefully and understand your concern. His symptoms are very similar to abdominal migraine attacks. This is a specific type of migraine, which is more common in children very rare in young adults. During these attacks besides headache, severe stomach pain, nausea, abdominal cramping, and often vomiting may be present. The weight loss is normal in this situation, because of the loss of appetite and vomiting. As you refer all the lab tests performed are normal, which is in favor of a primary headache like migraine. I would recommend to avoid all the factor which trigger migraine attacks like chocolite, wine, the noise, the sunlight etc. I would recommend also to use triptans like sumatriptan or rizatriptan during the attack and to take a lot of fluids ( water, juices). An antidepressant may be necessary to take for a long time as a preventive therapy. I recommend consulting with your neurologist on the above mentioned possibilities. Hope to have been of help! Greetings! Dr. Aida