My friend fears he has ocd and can't control "bad thoughts" that he keeps having. thinking about these thoughts he knows are wrong gives him anxiety.

Have friend get help: Have your friend talk with a health professional about these "bad thoughts". He can also post a question here for himself, and get a better answer. Urge him to seek some help, good treatment is available that can help him control these thoughts. A psychologist trained in CBT psychotherapy would be a good source of help. His MD may be able to give him a trial of meds also.

Therapy?: Has your friend yet tried any form of psychotherapy? Typically, the optimal combination of things to treat emotional issues such as OCD, anxiety or depression is medication (which, on your friend's best day best day, is supposed to take the edge off symptoms) but the real gruntwork takes place in psychotherapist's consulting room.

Helping OCD: It sounds like your friend is in need to consult in a mental health clinic or ask his doctor's advise in order to get treatment. OCD is usually a persistence and disabling condition if it is left untreated. There are multiple medication as well as behavioral approaches available. It would be great if you encourage him to ask for help.