Sick betta 😔

[Tyler]

So a few days ago I noticed my betta swimming really frantically and scratching his gills everywhere he could. I added general cure to his tank(5 gallon heavily planted at least weekly water changes) he seemed to stop scratching a day later but then I noticed very slight fin rot starting on one of his side fins. I added maracyn. Over the last couple days of treatment he has only seemed to gotten worse... He seems to have a fungus growth all over his body. I also started adding an ich treatment the day before yesterday too. He is now extremely lathargic, swollen abdomen, and just hides under a catappa leaf all day... Is the medicine making him more lathargic while he's healing or does this sound like he's not going to make it? He also stopped eating after I added the general cure. He's only been about 3 1/2 days since this started. I'm prepared to euthanize him with clive oil if needed... He is a veil tail betta from a chain pet store, but I didn't know of the many problems they usually develope with age. I've had him over a year now but he was definitely at least a year or more when I got him as he was already to his adult size. 

[Colu]

What are your water parameters and can you take picture of sick fish

[Tyler]

Just now, Colu said:

What are your water parameters and can you take picture of sick fish

My temp is around 72 degrees, been the same pretty much the whole time Ive had him. We live in Florida so room temp is pretty warm. I use r/o water in his tank and did a huge water change before I added meds. Tds is pretty low probably around 200 or less. He just floats here or lays on the ground. I think he's dead sometimes cuz I can poke him and nothing happens but then if I watch for 15-20 mins he will move a little bit. If u want I can try for a better pic. 

[Colu]

I would do a water change start treatment with API fungus cure and maracyn you can also use aquarium salt with fungus cure and maracyn 1 table spoon for 3 gallons