No, if you did a D&C you would lose the other twin. Generally a vanished twin simply fades away after a while, the body reabsorbs it. Good luck.
Depending on the time you miscarry. I was pregnant with triplets and miscarried my identical twins at 8 weeks. Needless to say this was early and the process happen naturally. I continued to carry my little girl to full term and she is happy and healthy now.
I'm so sorry. I don't have an answer for you...(what does your doctor recommend?), but want to say that i'm sorry you're going through this.