I dont know what the protocol is for FI sister invovment in the wedding. I was planning on a very small wedding party involving my best friend as my moh and my FI best friend as his groomsman. I later found out that my FI family was very upset that I didnt ask his sister to be a bridesmaid and had to go back and appoligize for "being so thoughtless". I didnt know if this is a major faux pas on my part or if they are blowing things up? She is now a bridesmaid so it is over and done with I just wanted to know some other opinions.