Trisomy 18. Decision to Terminate

I am 12 wks pregnant with twins.  I was told on Weds that things did not look right with one of the babies on Weds.  Had a CVS done on both twins yesterday.  The results came back today saying Trisomy 18 for baby A.  Baby B ( we now know is a boy) is healty and strong.

The Doctor wants to schedule the termination next week.  I have been reading online and the life expectancy (and quality of life) does not look good for Trisomy 18.  The Dr also stated that I am likely to miscarry Baby A and the longer I carry puts my healthy baby at risk.

What exactly is going to happen?   Has anyone here done the the selective termination?  How many days of rest will I need after?

 They did not tell me if baby A was a boy or girl over the phone.  Honestly...I guess I am trying to distant myself emotionally from the child, so I didn't really push for an answer.  I feel horrible for how matter-of-fact I am being about this.  But then...I may still be in shock...idk.