Andy, I was thinking about you and your situation the other day--glad to see a new post from you!
I took a class here at work called "Love and Logic." It is about parenting kids in a way that made a lot of sense to me--putting responsibilty on children in a way that makes them feel successful and loved. Anyway, you might want to check out the website: http://www.loveandlogic.com
Sorry to hear about your sister. She must feel like she can get a lot of support and understanding from you.
So, how do you feel about hitting that 2-year marker and the possiblities that it brings?