Welcome to HCM,
Your brother is suffering from Typhoid
and hope,he must be improving,headache and fever are part of systemic illness mostly, with treatment it should settle down.
It is possible to have meningeal irritation
as cause of headache and toxemia
may be one of the reason for headache.
You can wait for few days if headache subside there is no issue but if persists a CT SCAN
or MRI may be done to rule out any pathology.