I'm so sorry for your loss..as fas as your Mom goes, she is probably looking forward to seeing your dad again which will help her deal with her loss
I wonder if after some time your Mom will join the group of abanoned witnesses that are set out to pasture so to speak?
I had the same experience at my JW hubby's memorial. ( I disassociated myself many years ago.) Some came up and hugged me and spoke to me and others stood right next to me and totally ignored me.
It had been many years since I had quit going so I didn't know many at his memorial, which was a good thing..
Many promised to stop by and visit me but no one ever called or came by. So much for their word..
Hugs Snoozy