Based on the details your father has developed post stroke
,which is not responding to anti psychotics, other cause of abnormal behaviour can be due to seizure
phenomenon (a type of fit with behaviour abnormality), which only can respond to anti epileptic drugs
Hence consult neurologist
for clinical examination and EEG is needed to confirm and anti epileptic drugs to be started.
Blood sugar and electrolytes also to be checked
Hope this will help you