Friend thinks they have a brain tumor they are 20 years old. they think this because they get temple headaches and eye twitching occasionally ?

Possible, unlikely: Your friend should consult a doctor (personal physician or a neurologist) to get a compete exam. While a brain tumor is possible, there are many other less serious possibilities including migraine headaches (more common in women), cluster headaches (more common in men), vision problems, and others. After exam if nothing serious turns up, consider alternative options such as CBT psychotherapy.

My response: There seems to be an epidemic of 20-somethings in California fearing they have brain tumors due to presence of migraine headaches. As mentioned multiple times before, brain tumors are rare, do not usually present with just headaches, and eye twitching is normally secondary to benign myokymia, or blepharospasm.