So my mum died a few years ago and this was the first family wedding (Mum's side) since then. Dad was not invited. I haven't asked why - all I know is that if Mum had been alive, he would have been invited.
My cousin is the bride; I am relatively close to her and other immediate relatives. My dad's absence from the wedding wasn't mentioned by anyone on the day itself, but he was discussed in general (he lives overseas but visits UK relatively frequently). I was a bit confused by this, as to me it seemed a bit rude to exclude him and I'd thought maybe my older, more etiquette-conscious relatives would have avoided him as a topic. But no, he was discussed freely 
I thought he didn't really mind not being invited, but Dsis and I have both got the feeling over the past 2 days that he was actually a bit hurt. Many of the groom's invited relatives were ones he barely knew, so it wasn't a case of 'But she barely knows him'. Dad would prob have politely declined anyway, but he'd have been grateful for the nod of inclusion.
AIBU to feel a bit sad for him? We were all there except him 