No reason to check another site.. we have a section on these forums specifically for helping sick bettas.. we also have information from vets and people who have taken care of fish/bettas for decades here too :)
Buoyancy problems won't fix with luck, and swim bladders don't get broken lol..
Can you describe his fins? Are they shredded, are the edges blackened and flaking off? Red? White fungal growth on them?
As for buoyancy problems, which could be from bloating or swim bladder disorder can easily be taken care of if that is all that is wrong with him-
Start him out on two teaspoons of Epsom salt- no dye or fragrance- per gallon, dissolve it and add in water conditioner before adding your fish to it.
Daily 100% water changes must be made each day, adding in the salt mixture each time. Keep him in the mixture continuously.. the baths you mentioned on your other thread is not enough to help him. Baths don't tend to do much for them overall.
SBD and buoyancy tends to take roughly 5-8 days in Epsom before they are better.
What are you feeding, and how much per day?
What is your routine on water changes?
Temp of the water?
There are different factors that will cause that issue, as well as different ailments that will cause it. But without more knowledge and information, or even a picture we can only speculate that he is having SBD, and can treat that accordingly (what I mentioned above).