Need to Vent....

Ok. So I need to vent and it's off the subject of foster care/adoption. My identical twin sis is pregnant (AGAIN). She has not had easy pregnancies and the first one ended in the still birth of my nephew at 7 months along. This was followed by 2 miscarriages and then my nephew was born in 2004. Follow this by a miscarriage and then my niece was born last Nov. Now my niece is 5 months old and my sis is 4 months preggers again. I love my sis to death. WE are BEST friends (most of the time) and always have been. I'm happy for her that she is finally having the family she always wanted but truth be told I'M JEALOUS! She married into money and has no problem flaunting it. While we are not rolling in the bucks we do quite nice and are happy with our life. The problem is she is CONTINUALLY complaining about being pregnant. She had a rough pregnancy last time and spent the last 2 months on bedrest. I wish I knew how to make her understand that although she is uncomfortable I would do ANYTHING to have her problems. Then last night she gives me this sob story about going to CO this summer for a convention and her hubby is soooo busy with his job that she's going to HAVE to ask my mom to keep her kids for the week. Give me a break. I have a brother/sis-in-law that live in the same town as she does. She doesn't have her kids in daycare in the summer normally but I know her daycare lady would take them since she knows this far in advance but why pay daycare when mommy can do it for free??? My mom is not in the best health and should not be caring for 2 young kids. Granted my dad is there too but he does work all day. I'm just sooo tired of listening to her complain. What can I say? I don't want her mad at me but how do you make someone understand that her whining is driving me CRAZY!!! Any advice out there???