Children need to be in control to feel safe and secure in the water.
They feel in control in shallow water where they can stand or sit and learn by exploration and encouragement. For Isaac to feel comfortable and in control, he needed to stay on the steps where he remained for five full lessons. This is not the case for all children.
Every child is different, and you need to allow them to progress at their own pace.
Some children master breath control and are independently floating within the first few lessons, while others need more time. But forcing a child to overcome their fears will only prolong the process, and they will lose your trust. It takes a lot longer to regain a child's trust than it does to earn it.
Here's part three of Isaac's second lesson, where I encourage him to practice putting his face in the water with a fun song.