For me, being the mother of a boy who is only 4 months older than Miles, I was really struck by the seriousness of what happened, and how bad it could have been. I'm even more vigilant about watching Aaron near water, and we keep him in his lifejacket most of the time.
Since Aaron wears his lifejacket so much, I've once seen him boldly follow Austin into the sea from the shore, he was submerged, his blonde hair floated up, then he surfaced, sputtering and crying. Fortunately for us, we all saw what happened and Austin was right there. Aaron is so accustomed to being buoyant in the water, that he is less fearful now, and he's not always aware that he's not in his lifejacket. I think Miles may have thought he still was wearing his water wings when he went into the pool to fetch his boat (he told his mum he was trying to get his boat when he went into the pool).
I noticed that Miles was found floating on his back. All my kids were afraid to swim on their backs when they first learned to swim, and Aaron is still terrified of this position. Miles was practicing leaning back into the water earlier in the day, with his mum. His big sister is a very strong swimmer and he's seen her swim on her back a lot. We don't know how long Miles was in the water, but I think he was better off on his back and able to get some air. I want to start helping Aaron to get more comfortable lying back in the water.
Austin's calm response and the absence of fear and panic in his rescuers has left Miles with a positive memory of the event. He told his mummy that he went "swimming under the water." He doesn't think he had an accident and he isn't more fearful of water. I remember a swimming instructor telling me that it can be difficult for parents to teach their children to swim, because the parents are too nervous about letting their little ones put their heads under water. Sometimes the parents, themselves, are nervous about being submerged. I remember that teacher being able to get Austin, at the age of 1, to hold his breath as she glided him underwater for a couple seconds. The technique was to blow air into his nostrils, then immediately bring his whole body, head first, under water. I have to admit that I was always hesitant to do this move. I'd blow into his nostrils, see the look of bewilderment in his face, then take him underwater too late, or I couldn't bring myself to take his face into the water at all. Anyway, I was reminded how much it helps people to learn to swim with teachers who are confident swimmers.
My final observation is that, when there are several adults supervising together, it's easy for us to have a false sense of security and to let down our guard. After this experience, I hope to be even more careful about keeping our kids safe around water.