I can't speak for schizophenia but my 98-yr old auntie with advanced dementia talks non-stop. Non. Stop. I don't feel obligated to respond at all. I will often just go about my business or walk away to another room.
No one on this forum can tell you the source of the chattiness, but if it's driving you crazy and you are your dad's medical PoA, then you should discuss it with his doctor.
You will need to consult his psychiatrist for answers to this question.
Do you want to discuss other issues? Perhaps if you share a bit more about dad’s behavior someone will be able to help you.
Best wishes to you and your dad.
No one on this forum can tell you the source of the chattiness, but if it's driving you crazy and you are your dad's medical PoA, then you should discuss it with his doctor.