Hello and welcome to HCM.
Thank you for your query.
The exhaustion that he is exhibiting could be the presence of the
migraine headache, that is quite debilitating. A migraine is relieved with rest and medications. And depending on which medication he is on for his migraines, we can help in ruling out a drug cause. The most common side effect of migraine medication is gastric irritation, and increased acid production, that could result in temporary
abdominal bloating and gas production. This can result in a mild headache as well. This can be relieved by consumption of a small meal before taking the migraine medication, or even after, along with some antacids.
Beta-blockers like propanolol are commonly prescribed for migraines which can cause
fatigue in an individual. If he is abusing this drug then it is best to report this to a doctor, as beta-blocker abuse can result in serious side effects.
It is best he seeks help from a doctor for his migraines, which will avoid a recurrent migraine attack and advise on lifestyle change that is also vital in preventing migraines.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you.
Best wishes.