What Causes Stomach Ache And Headache?

hi my brother has been sick for a while, complain of stomach ache and he collapse, his skin was yellow on sunday, he has terrible headaches, and this morning he vomited blood, he keeps on being tired and sleep most of the day, on monday a dr took a scan of his brain and found a cyst, so he must go see the neuro surgeon in january, i just need to know what can cause him to be so sick?