Well not technically SIL as DP and I not married yet, but she is one of my best friends as well, so am very honoured and excited
Is there anything I should know? What do I do? She has done the basics of a birth plan and I was with her when she wrote it out so I know roughly what she'd like (she's not due till Sept) but wondered if the collective wisdom of mumsnet had some tips on being the best birth partner I can be for her I had DP with me when I gave birth and I was glad of his company but he didn't play a very active role tbh so nothing to draw on there.