What Causes Blood On The Brain?

My son was diagnosed with the flu last Thursday, he became dehydrated and they said he has blood on the brain they are not sure why,, they have done MRI's, EEG's, CT, Spinal tap and thye still don't know what is going on? they said maybe he had a mini stroke, maybe seizures,, they said maybe we never know.. I just know it has been 5 days and he is still extremely sick., and fevering... and we has where his eys lock toward the nose,, he whimpers like he is in pain IS there anything else I can suggest they test for