Also, as difficult as it is to say this, I would discourage buying an animal that is already sick. To start, you are getting an animal that will likely need more money put into it because it is unwell. It also makes it difficult to diagnose because you don't 100% know the conditions it was in. Another reason is the store you buy the sick animal from is only encouraged to get more animals which will likely also get sick, creating a sad circle of poor animal health.
I hope he makes it.For future reference, try putting questions in the Pacman frog forum here instead. Otherwise, people will likely miss your threads and you'll get more people to see your questions.
EDIT: I originally asked if his other frog had passed because I missed the part saying he had multiple Pacman frogs. Oops!