Can seizure medication be backed off?

My son is 5 and has autism and epilepsy.  He was put on phenobarbitol a year and a half ago and hasn't had any grand mal seizures since.  But, he did had a milder one a few months ago.  He didn't collapse.  But, he turned grey and it lasted about 30 seconds.  Even so, our neurologist wants to back him off his phenobarbitol from 3 to 2 tsp a day.  He said he wants to see if he's "coming out of it".  I thought that epilepsy was life long.  Honestly, autism has taken up much more of my reseach and I don't hear as much about epilepsy.  So, any responses would be helpful.  Does this sound reasonable?  I am very concerned and wondering if I am overreacting.