There are medications for raised scales and dropsy, but I haven't heard of a fish recovering.
If he's not eating, put it a food stone (Like the ones you put in when you go on vacation) so he can choose when he wants to eat.
Raising the temperature may accelerate his condition, however use your judgement.
Cleaning the water will help prevent other sicknesses from attacking his now weakened immune system, but be prepared, as he might contract other diseases.
When my brother's fish had dropsy, aside from giving him medication to treat dropsy, I gave him a salt bath, which dramatically improved his attitude.
However, it did not stop his death.
I have read of people buying very small needles, sedating their fish with clove oil, and removing the fluid that causes the swelling, then treating the wound with concentrated salt water.
This is a temporary solution, and although the fish's health improves, I have again never heard of a fish surviving for very long.
So sorry to hear that your fish is going through this, and I hope he gets through it okay.