You're a very wonderful and thoughtful SIL!!

One thing I will say. Don't whinge about your pregnancy symptoms in front of her (sorry, I know you probably won't). This is the one thing that really upset me. And the belly rubbing. I wanted to punch things when my pregnant friends rubbed their bellies when I was around (whether they knew of our LTTTC or not).

What everyone else has said is really helpful too. I guess just being there if she wants to talk and listening to her without offering advice or solutions.

Huge congratulations! I hope that your SIL's IVF cycle is successful and you're hearing a pregnancy announcement from her soon