Ahhhhh!
"Anal retentive" = "OCD" = "ADD" = PIA!!!
VERY hard people to deal with. Your sister has my sympathies.
Hmmmm ... how about a WebCam for Christmas morning? One at your place, one at theirs ... It's a great way to "share" while maintaining a great distance
. And your babies will be happy - and you, too! Maybe even your mother ...