I would be p*ssed if my BIL put me in a position to lie and/or omit telling SIL about the visit. If the lady's brother doesn't care he's a selfish ass, that's fine with me, but don't expect to lie/cover it up for him. SIL is going to be hurt when she finds out (and she will eventually). And why? because BIL wants to be sure all the attention is focused on his child.

I would have a hard time with this request. I am going to assume if he's driving 12hrs, he'll staying more than one day? I could understand maybe a day or two centered around him and his family, but keeping the entire visit a 'secret' and intentionally keeping SIL and her little one out...that's just wrong.

I know when my aunt has come to visit the long weekends with her sister (my mom), mom usually has them Friday evening for a relaxing evening. Saturday's are usually everybody come mid afternoon and we all have dinner and visit. Sunday then mom and her sister do church and brunch and spend the afternoon either quietly visiting at home or doing a site seeing afternoon. Monday's off Aunt goes to drive back to her home state.

I would think your BIL would want to visit with his sister and see his niece at least one of the days of his visit. Was he close with his sister prior to the birth of the tots? And what about the SS? Is anybody 'allowed' to show SS a bit of attention or is that a no-no as BIL's little 2 yr old may feel slighted if she isn't the center of the entire visit 24/7.