My father (80) sits like a statue with his mouth open for more than five minutes. Why?

Thank you for your responses. I will take him to his doctor and explain everything

Episodes of non responsiveness can be part of dementia also. Does your father have any other behaviors or symptoms that might indicate dementia?

In any case, his doctor should be consulted about this.

Absence seizure or TIA. See a Neurologist. Keep a log of dates, times and duration of any seizure or altered consciousness.

Is this a new occurrence? I was thinking the same thing as CM, that they could be seizures.

If your dad is still mobile, I'd be quite worried about him falling during one of these episodes. I would call the doctor today and ask for advice.

Ummm... absence seizure?

But hadn't you better mention this to his doctor? You'll need to tell him or her when it started, how often it's happening and whether or not these episodes are getting more frequent.