How are you acclimating him to the new water? Are you making sure that the new water is the same temp?
Your water change routine is not going to be enough. This needs twice weekly 50% and 100% water changes.
You should use the in tank thermometer to match the temp of the new water, and mix it up with conditioner before using it to make the changes. For the 50% change you can leave him in the tank. For the 100% change he should be scooped up into a plastic solo type cup and set aside while you rinse the tank and refill it with matched temp water and conditioner. Then he should be floated in the cup inside the tank for an hour while you slowly add a couple tablespoons of new water into the cup every 10minutes. When you release him, try to let as little of the cup water into the tank as possible.
You do not need all three conditioners. That's a lot of chemicals he's being subjected to. Tetra Lifeguard is a medication. This needs to be discontinued. Tetra easybalance messes with ph and I also suggest discontinuing it. Choose between Bettasafe and Aquasafe they are basically the same thing, one more diluted than the other
I'd get him in some clean stable water without all those chemicals and see how he responds in a few days.