A Little Apprehensive....

My big sister, April, has had a rough year.
In February she was sentenced to a federal prison.  She spent about six months there.  I never went to visit her, though I allowed my mother to take my daughter for a visit.  I never talked to her on the phone, except once when my mother sort of tricked me and I made a quick exit, and we only wrote letters.  I have some old issues with my sister.
After her six months she was released to a rehab facility.  She was picked up at her prison an hour south of us by my mum, and taken to the rehab that is three hours north of us.  She had a brief layover in our city to see the family.  I barely talked to her but we were civil. 
She then spent five months going in and out of rehab.  She was picked up twice on minor rule infractions.  Recentley she was granted a sort of release.  She goes into a home that is run by a drug free clinic.  She is prone to random drop ins, random screenings, and it is mandatory that she attend a certain amount of NA meeting and counseller meetings in a week.
On her travels she picked up a girl friend.  I have no issues with that.  I've always known my sister is bisexual, this hasn't been her first girlfriend.  My biggest worry is her gf is also a recovering addict. 
Now, my sister gets to come home for a week this holiday.  And I am freaking out.  I've gone almost a year, shamefully, pretending that my sister was on a nice vacation.  Or simply pretending that she lived so far away we just had no contact.  We brushed the surface of our issues but didn't really delve into anything.
I feel like I'm going to be meeting not one, but two strangers this Christmas when she brings home her girlfriend.  I don't know what to expect.  And my stomach has been practicing it's flips when I think about how this is going to go.
No holiday has even been a good holiday with my sister.  Even before the addiction she was very self centered.  If it wasn't about her then she would make it about her any way possible.  We have had good birthdays, a good Thanksgiving, a good Halloween.  What if she hasn't changed and she comes home just to ruin Christmas?
Worse yet, what if she doesn't??  I don't know how to handle a mature, responsible, action owning April.  I don't know how to respond to someone who acts like a functional person.  I know how to throw out the addict, I know how to console the sobbing children, I know how to change the subject before the screaming starts.  Those things I know.
Ya know, she has been clean for a full year.  Yet the addiction still has tendrils in my life.  How do I get them out?  I don't want to think about the old April.  I want to take this up as if I'm meeting a new big sister.  But I can't...