From what my sister said (I was out of town this weekend) he seems to be doing well. I went to the store on Friday before I left and they said try some bettafix because he was a tad pale and also kinda lethargic. Within half an hour of adding it, he ate 3 pellets. We dosed him again yesterday and today and he has been eating (or so she thinks-->my sister hasn't been able to watch him very closely since she works at night) what she's given him. I will keep an eye on him for now and give him some more bettafix as needed. If not I will try more food brands (the store said wait until I tried so bettafix.) As for the snails they are coming out of the 5 gallon with Rubeus. I still have a smaller tank that I will keep them in where they can go get it dirty as much as they like and I can clean it easier. They're not my favorite by a long shot. I got two after my one died and then regretted it. I won't have them again THAT'S for sure. I'll keep everyone updated!
I wouldn't keep adding Bettafix, it's supposed to be used if the fish is injured, the store was just trying to sell you a product. There's also some debate in the betta community as to whether the product is safe or not...many believe that the ingredients negatively affect anabantoids like bettas and gouramis. For that reason alone, I don't recommend the product for bettas (which includes Melafix, the same thing in a different package) and if it is dosed, use half a dose and don't dose every day. If you saw any improvement, it was not because of the Bettafix...it is not a medication. He's probably just acclimating

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Remember to test ammonia and nitrite asap. It sounds like a well-maintained aquarium but two apple snails (even temporarily) and a betta in a 5-gallon is overstocked so regular water changes are a must. Adding some fast-growing live plants (java moss, water sprite, duckweed, etc.) could also help

. When you move the apple snails, a great alternative is the smaller freshwater nerite snail (sometimes called "tiger snails" because some are orange with black stripes). If you want any more snails, that is.