Hello,
Absence seizure does not cause loss of consciousness.
Delusions would most probably be a part of his illness rather than due to seizure.
If you would mention his treatment details, i would be able to give you a better advice.
The treatment of bipolar disorder depends on phase of illness. The manic phase require a mood stabiliser like divalproex or lithium.. And as you mentioned that he has delusions, he would also require antipsychotic drugs like olanzapine.
The depressive phase requires antidepressants only if the depression is acute and that too alongwith mood stabiliser. Otherwise antidepressants are better avoided and never to be given alone in bipolar disorder.
Hope this information is helpful for you.
Thanks.

Hello welcome to HCM

Bipolar disorder is a mood disorder and usually mood stabiliser drugs are used for treatment of excitement of bipolar disorder. Your father is on medicine for 1 years and with poor response. Now doctors have diagnosed him with absence seizures. See most of mood stabiliser drugs are anti-epileptic drugs also and they can control the seizures effectively. You have not mentioned which medicines he is taking but most likely he is on mood stabiliser so there is no need to take treatment of absence seizure again. The fainting might be one of symptom of absence seizure or it may be occurring due to postural hypotension.
I would recommend you to get his EEG done to confirm diagnosis of absence seizure and to ascertain seizure focus. Consult your doctor for reevaluation.

Thanks