Hi... Welcome to healthcaremagic forum...
Intracranial bleeding is of different types - concussions, intracerebral bleeds, subdural hematoma
, subarachnoid hemorrhage
and extradural hematoma. These along with the amount of blood, the pressure effects of this blood on the normal brain decide the outcome of the condition.
Hence without a proper physical examination and review of the scans, it's a hard task to answer your queries.
Yes, most of these condition resolve with time and medical drugs are useful to prevent further bleeding, support life during these stage ( as things can worsen during a week following injury
Blood can be drained out via burr hole, if entailed.
I expect your headache to come down spontaneously after a few weeks ( as there is spontaneous resorption in case of small bleeds) or following surgical drainage
of the blood. In the mean time, pain killers and anti odema drugs (osmotic diuretics) may be used under the guidance of the treating doctor for symptomatic relief from pain.
I wish your nephew good luck and faster recovery