The minute she came on the stage, he yelled "Hey Annie, it's me, Mikias!!". Kurt did a great job of helping him understand that we needed to sit quietly and watch.
His Annie obsession lasted another month or so and then our boy was on to new obsessions, like legos. A few days before Bethe arrived Kurt asked Mikias if he remembered thinking she was Annie. He didn't. In fact, he didn't seem to remember his Annie phase at all.
When we see Bethe, we like to greet her with "You Annie?" Mikias may not remember, but we will never forget it.