Please never flush fish! (and tell your friend I said it).
Firstly, flushing dead, tropical fish could potentially introduce foreign pathogens into your native water course. It is also frequently illegal to dispose of dead animals in such a way. Wrap the fish in newspaper and put it in the dustbin please.
Secondly, flushing a live fish doesn't immediately kill it, since fish (pretty obviously) can breathe water. Instead, the fish is slowly burned by chemicals and sewage and choked to death. It's a long, slow, painful death and no pet deserves that. Please read the pinned posts on humane euthanasia or follow the discussions on this site (do a search).
I commend you for your concern for this poor fish. Mollies can be a bit crazy, even when healthy, particularly the males, but if there is something terribly wrong with this molly the first thing to check is water quality. So take a sample of your tank water down to your Local Fish Shop, particularly looking at your ammonia and nitrite levels. Your tank is probably not cycled so you're going to have to do some work to get it there. Please follow the link in my sig and read about setting up a New Tank.
In the meantime, I agree that Maracyn (fish medicine that you can get from your LFS) is a good recommendation. However, this fish may be suffering from lack of oxygen since mollies don't cope well with over-stocked tanks.
I went over to a friends house just a while ago and he had a tank full of fish I noticed one of the fish swimming in circles I dont know if it was in bad water or not I ask him if I could have the fish and he gave it to me. So now I have a mollie that is swimming funny I put it in some salt and added some maracyn to the water are they anything else I could do for her or what does anyone think that could be wrong with her to make her swim like that. I am open to any ideals I know it is more than likely hopless but I couldnt stand to see it do the way it was doing without trying something.He told me he was going to flush it before it made the rest of his other fish sick. That is the reason why I have it I couldnt stand the thoughts of him flushing it so I have a sick mollie on my hands now I need to try to make her better.
