Dying Leucomela

Hello all,

Short background. I currently have 2 leucomelas and 2 powder tincs. The tincs are over 5 years old and very healthy. My Leucs have been active and healthy for the 2.5 years I have had them.

About a month ago I realized one of my Leucs was much thinner than the other. Ironically the other looked fatter than ever. I assumed early on that the bigger one was bullying the other. I had never witnessed any violent behavior, but I still began purposely putting dusted flies near him to make sure there wasn't competition and he had time to eat.

Fast forward to a week ago, they were both out on the tank floor together and he was looking scary thin. When I went to feed them both, he flipped over on his back and stopped moving. I helped him over, he hopped around (poorly), and then flipped again. At that point, I removed him from the tank and put him into a clean unused 32oz ventilated deli cup with some wet sphagnum moss, leaf litter, and dusted flies. I realize now I should have used paper towel.

Now a week has gone by, I do not think he has ate any flies, and he hardly moves but when I lift the cup he either blinks, flinches, or moves a limb.

Is there any saving this little guy? The other 3 seem extremely healthy, so I am wondering if this is out of my control. Thanks so much.