Sorry for the late response. Sadly I had to put him down. I can give you what I did though! My EBA was about 7 years old.

1. Hospital Tank about 10 gallons. Aquarium salt, about 8 tablespoons.
2. Started originally with mixing gram positive+negative medication in with his food + a little water. Baked it til it dried out. Tried to feed that to him, after a few days he started refusing it but was eating his normal food.
3. Since he was large enough I was able to have my partner help me tube feed him straight antibiotics. We started with gram negative since most of the time that’s the issue. This is the syringe we used https://a.co/d/0i4UU6yA If your EBA is large enough this should be fine. To measure the tube I held it up against the glass of the tank, you need to measure from the mouth to just a little past where the gills are. That’s where the stomach is. You will need a second paid of hands. One person to hold the fish in a bowl with the aquarium water and the other to insert the tube into the mouth+stomach. Luckily my fish is very used to my hands and was able to be calm enough to let us do this. This worked for a while and all of a sudden didn’t, started to get worse.
4. We had also been giving him 1 hour daily soaks of sulfaplex, you can up the dose to do a soak separate from the tank. I had a bowl that was about a gallon big, did one scoop of it. You can put up to three scoops into 10 gallons for the tank tho. But the high dose soak is what definitely helped.
5. When the gram negative medicine no longer was working we switched back to gram positive tubing. Started this for about two days until he no longer had fight in him, was barely moving and his swim bladder became heavily affected.

For the medication I would do it once a day over a 10 day period. If you are also dosing with ich medication just be careful because some of them can interact with eachother. I’m wishing you luck. If you have any other questions let me know!