DD1 had terrible night terrors from about that age to age 4ish (sorry!) and we didn't find a way to manage them other than to sit them out and make sure she didn't injure herself. We did notice they were more common when she was overtired though...
Sorry, I'm no help at all but just wanted to give you a bump because I know how frightening they seem. Hope someone can come along and give you some good advice
You're supposed to make a note of what time they happen, then wake them up just before that time to break the pattern. We never really did that but we found that ds had to be woken up properly or he would just carry on screaming and sometimes walking round and round for hours, and the best way to do it was to sit him on the loo. He's 6 and still has them occasionally though thank goodness not that often now. It was scary and upsetting at first but you get used to it.
Just to echo what Emmalina said - my friend's son has had night terrors for a few years and, again, they've been advised just to sit them out and make sure he is okay. Tiredness is the big thing for them too.