Chronic confusion related to degeneration of cerebral cortex secondary to alzheimers as evidenced by pt not being oriented to person, place or time, self care deficits, MMSE score of 6 and combative behaviors."Self-care deficits" cannot be a symptom (evidence) that supports that the patient has disturbed memory, orientation and behavior (part of the definition of Chronic Confusion). I would just use any of the self-care deficit diagnoses.
While it is probably OK to include combativeness as a symptom of this diagnosis, I would use Disturbed Thought Processes or Risk for Other-Directed Violence.
Here is a weblink to a page on the nursing diagnosis of Chronic Confusion and Disturbed Thought Processes: Chronic Confusion, Disturbed Thought processes
Goals are going to be based upon what you expect to happen as a result of interventions you are going to be ordering for the disorientation.