Your father needs to be assessed by a clinical psychologist
for extent of dementia
,once dementia is confirmed the medications are available which delays the process of degeneration but does not cure it . Medications are also available to control aggression.EEG needs to be done to evaluate for seizures which can coexist in some cases
Medications for depression
also help when given with antidementing drugs.plz consult a neurologist
,he would be able to help you.