What predisposes someone to bleeding in brain?

Depends on age: If it happens to a baby, it could be because of prematurity or because there is an abnormal connection between an artery and vein in the brain (av malformation). In older individuals a stroke is the most common cause and also an anyeurism can cause bleeding.

Hypertension: Hypertension is the most frequent cause but there are many others. Blood thinners, trauma, tumors, aneurysms and other diseases of the blood vessels.