I still don't know what the white patches were. They didn't look like any if the columanuris pictures I found online. They weren't fuzzy or cottony or anything. More like a discoloration and the gill that was worse looked slightly raised and as he got better, the scales were shiny silver with a blue sheen. Not like a fungal growth at all. I think we all ended up thinking possible amonnia burns or similar. There's loads of photos in my first thread (titled "my son's betta is very very sick").
He was responding really well to the daily 100% water changes and AQ salt. But his dorsal fin just started deteriorating and wouldn't stop. And then the bubbles. :( The bubbles happen when he takes a breath in - its like the air just comes straight out his gills. It also happens when he eats.
He's had some breakfast just now but he's still very lethargic and not happy. Every time I look at him he's resting on top of his plant, but he wiggles around and swims to me whenever he spies me. Poor little guy. I never thought I could love a fish this much. And I feel so terribly guilty because I did this to him by following what the pet shop told me to do, instead of what I thought was right. :(