A. Well, if he is having a night terror, and it sounds like he is, then it is important to keep in mind that he is not really fully awake during this time. That is why he doesn't recognize you and he seems confused. Night terrors are thought to be a disorder of partial arousal, which means that your child is partly asleep and partly awake, and so you wouldn't really expect him to be thinking or talking clearly.
Instead of trying to wake up a child having a night terror, it is usually better to just make sure he is safe, comfort him if you can, and help him return to sleep once it is over. So you don't necessarily need to talk to him like you are doing, unless you think that it is helping to comfort him or get him back to sleep.
And no treatment is usually necessary for routine night terrors. Since they are often triggered in children who are overtired, sticking to a good bedtime routine and making sure your child is getting enough rest can help to prevent them.
Since this is a new problem over the last 3 weeks, you should review his routine and make sure that nothing has changed that may be bothering him. Maybe he has recently given up his daytime nap or is going to bed later, which may be making him overtired.
For children who get frequent night terrors, it might help to wake your child up before the time that he usually has a night terror. This is thought to interrupt or alter the sleep cycle and prevent night terrors from occurring (it also works for sleepwalking).
See our guide to Night Terrors for more information.