Hi welcome to the forum. Sorry it's under bad circumstances that you had to post. :-(
I also have a scooter that was sold to me as a blenny and I was told it would eat anything. Well, as it turns out the scooter isn't really a blenny but a dragonet that only usually eats live food like pods
that you get in an established tank.
I tried for days to find an LFS
that would take him but no one would so I had to keep him. It took about a month but i managed to get him eating frozen food. i would get some pods
and put them in the tank every few days if possible (turn the flow off when you add) and start trying to get him on prepared foods. What I did was shut the flow off entirely and i used a turkey baster to get the food to him. I started with frozen foods like cyclopeeze which is tiny and every day i would feed different frozen foods. After awhile he finally started eating it and he prefers blood worms now. You can also get some live brine shrimp and feed him those.
It may be too late but I would definitely give it a try. Just try to have some pods
or live brine so he can last the time it can take to get him eating prepared. I luckily had a fuge and a good amount of live rock and pods
already so mine had something to eat while he was being weaned.
good luck!! I hope he comes around.