Yikes. Luckily my family is computer-literate enough to set up a computer and I live in a different town so I'm not expected to help with that stuff. However, my mom DOES do that to me too.
I was going to a wedding and didn't know what church it was in and I'm driving around this town calling everyone and no one would answer. Finally I had to call my dad who wasn't even going and was at work. Him: "Why didn't you call your mom???" =.=
Thanksgiving was messed up here, too. Fortunately I didn't have to be there early, but we usually go to my dad's sister's house and then to my mom's parent's house later. This year (because my grandmother died, I guess?) we spent the whole day at my mom's side instead, but she never bothered to tell me or my sister that beforehand.
At least you apparently live in the same house and can ask. I have to rely on *possibly* getting a one-line email telling me what's going on at any given time. Mine aren't quite as bad as yours, but if they were they'd find me telling them "no" all the time. They never had very good control over me, though. ;)