Well, they are sick, for sure. Because mold does spread, I would make sure the mold cannot reach any of your other roses. Depending on how valuable these particular plants are to you, you may or may not want to treat them with a fungicide and plant them in another area of your garden to see if they come back and are healthy. I would also treat the soil where these roses were covered with a fungicide to try to stop the spread. And watch the other plants very closely.