Hello dear, Thanks for being on healthcaremagic.com. If you would have presented to me as an outpatient,I would have made the following clinical explanation- Single episode of unilateral headache can be a primary headache or a secondary headache.Most commonly, it results from mental fatigue or anxiety.Please let him have some mental relaxation,a good sleep and see if it persists.I hope it will improve.If it persists even then,please follow-up and I may ask you some leading questions to diagnose it.Recurrent episodes of nasal bleed are definitely should be a cause of urgent evaluation by an ENT expert.It may be a high blood pressure,a nasal polyp,dryness of nasal mucosa or just by nose picking habit in some.It is however,not frequently related to headache.I hope it helps.