In front of her brother, there's probably no problem there. I mean, she's may have been doing that all her life, so the brother is used to it and doesn't think one way or another about it. I'm just guessing about this, of course. For all I know, her brother gets turned on about seeing his sister in panties. I don't really know. Or, perhaps, she is trying to get them both turned on.
However, in front of your husband. That is a totally different story. There's a right time and a place for everything and her walking around in her panties in front of your husband is neither the right time nor the right place. I suggest that you have a long talk with your sister-in-law.
However, in front of your husband. That is a totally different story. There's a right time and a place for everything and her walking around in her panties in front of your husband is neither the right time nor the right place. I suggest that you have a long talk with your sister-in-law.