Time passed by quickly. During these times, Alex would constantly bring Kai and Wendy to the very field where they had awakened to continue their training.
Henry and Emily were still unaware of this as that was what Alex wanted. Both parents thought that Alex was just trying to spend as much time with his little siblings before he starts to get busy. So, they did not raise any objections every time Alex would take Kai and Wendy out.
Alex had no plans of letting them know, so he allowed them to formulate their reasons without trying to correct them. Wendy and Kai were also doing their best in keeping their mouths shut. After all, their Powers were on the line here, only a stupid kid would exchange such godly powers for gossip.