Aw, Jesus. :-( That sounds like a tragedy (in the midst of a time where one is expecting/experiencing such joy) that one might never completely get over. You poor dear (and your poor sister-in-law). The idiot who said that will hopefully go to some especially horrific afterlife.

I hope that the passage of time will provide at least some measure of healing for your family and that you all have a much greater supply of supportive friends to help than you do of unfeeling idiot bastards who clearly don't think before opening their traps.