I've done some lurking/searching the forum and haven't seen this situation addressed, but forgive me if it has been and I couldn't find it.
My fiancé and I recently set our wedding date, and were sure to ask our VIPs for dates that wouldn't work prior to placing our deposits. At the family dinner where we shared the finalized date (in May 2014) my FSIL indicated that they were considering going away around that time, but hasn't booked anything yet. I thought it was weird that she would mention it, but didn't think much of it at the time.
Fast forward a few weeks and FSIL and FBIL (the best man) announced that they are expecting a baby. This is all around great news and we are psyched to have another niece or nephew. Unfortunately, her due date is the same weekend as our wedding. While this is no guarantee that she or her husband can't attend, we also don't want to assume they'll be there.
My question is how to politely indicate that we completely understand that the Best Man has other priorities more important than our wedding without making it sound like he's being un-asked to be best man.
Is it appropriate to make contingency plans like having another individual designated to be a witness or stand up with my FI? Is it just something we deal with the day of if it becomes an issue then?
My goal is just to make sure my FI has a great best man supporting him on our wedding day, while still being polite to his brother and any potential friend he would have stand in as best man. All of this is of course recognizing that the birth of a baby is way more important than the particulars of our wedding.
Any advice would be greatly appreciated.