I agree, the rat needs to go to the vet right away. Wheezing is a terrible sign, rats have such delicate respiratory systems and wheezing is very very bad. Any abnormal sounds are never good. Red disharge (porphyrin) also isn't a great sign, but isn't uncommon. I wouldn't say it's a very bad thing unless it's associated with something like wheezing or other noises because sometimes it only means stress or lonliness. (Maybe there is a bit of lonliness too --- I think the ratty needs a friend Unless he/she is too old).

In the mean time, before the rat goes to the vet, make sure your friend takes the nessecary precautions so that the rat will stay alive. I'd take any shavings (escpecially cedar or pine!!!) out of the cage, because all shavings do contain some dust, and then put some clean rags or cloth down instead. Atleast until the rat goes to the vet. Also give the rat some real chocolate, only the size of a chocolate chip, nothing more, because the chocolate will help open the airways so that the rat will be able to breathe better.

Please make sure your friend takes him/her to the vet! It's very important.