Death from Cerebral Edema

My brother recently passed away from what appears to have been a bad seizure that cut off oxygen to his brain.  He was 36 yrs old.  That morning he got 2 seizures.  He "came to" from the 1st one but not from the second.  He was transported to a local hospital & given a CT scan that revealed 75% brain damage.  He was then transported to a bigger hospital 45 minutes away & given another CT scan.  He spent a week there & the main focus was the cerebral edema he sustained.  The doctor at the 2nd hospital told us they compared the 2 CT scans & that my brother's brain swelled very rapidly from one hospital to the next.  At the 2nd hospital his brain was already swollen to capacity.  He said it was something he'd never seen before in all his years of medical practice & one he could not explain.  As he put it, "It's a big mystery."  Our family refused an autopsy even though it may have given clues as to what actually happened so now we may never know if something other than an epileptic attack caused his death.  My questions to all of you:  have you ever heard of very rapid cerebral edema from an epileptic attack?  Is it likely that SUDEP occurred?  Up until all this, we had no idea that epilepsy could kill like this, IF IN FACT HIS DEATH WAS DUE TO EPILEPSY.  Any light shed on this is greatly appreciated!