When I started having seizures (complex partials) they were ALL at night but woke me so I was well aware of them. It was months before they moved to daylight hours too.

If you would have a Video EEG in your hospital any seizures would be easy to spot.

I spend some time in a brain tumor forum and lots of the people who have had brain surgery for tumors develop seizures. There it is very common.

Best wishes.