Leanbo, I'm so sorry that you are feeling hurt and angry. I agree w/ those who say you probably weren't told about OGS joining the military b/c of your negative attitude about it. They may have been trying to spare you the aggravation or worried that you would object and argue. If they decided not to tell you he was in the military, they couldn't very well tell you he was stationed in the UK either, I suppose. In fact, I imagine DD and family spent Christmas there b/c GS is there and b/c he and GDIL are expecting their first child. But I also think they didn't let you know they were going there b/c they didn't want to explain about GS' joining the military. No doubt, they could have avoided all these issues by simply telling you about his choice of career in the first place and letting the chips fall where they may. But they didn't, so I think that explains a lot else. It might not make it much better in your eyes, I know, but hopefully, it will ease your pain a little.
As for their not telling you about the coming GGC, that may be part of the whole effort not to mention the military. If they told you, what if you asked when and where? And if they said the UK, what if you asked what GS was doing there? Do you see where I'm going w/ this? It's unfortunate you ended up alone on Xmas though. Hugs! Hope next year, you make some plans w/ other relatives or friends.
Then again, I'm afraid GGPs are often overlooked. Parents have many people to inform - GPs, aunts, uncles, etc. so GGPs, I've noticed, often are "the last to know." A common oversight, not meant to hurt anyone.
As for DD's and GD's accident, I'm so sorry to hear of it and I hope they are ok. You must have been so shocked when you heard - and yes, embarrassed that DD's friend knew and not you. I totally understand your running over to the hospital, and it must have been very confusing when there was no record, etc. Though I agree w/ Hithere that GD was probably registered as a "private" patient, you probably didn't know that was possible or didn't think of it. I get that you were bewildered and upset, but agree w/ others that your "demanding" approach was a huge mistake. No doubt, you were worried about DD and GD, but you needed to show that concern, not complain about not being kept in the loop. In fact, I'm sorry to say, IF you have a tendency to cause drama and make things about yourself, that may be why you are finding yourself "excluded."
But I'm not sure what you mean when you say you're "excluded from everyone.' Are you talking only about these recent incidents or has this been going on a long time? Have you been excluded from several holidays, etc., for example? How often do you get to see DD and your GC, if at all?
I must admit your post is a bit confusing. My guess is you were writing it when emotions were running high, which is not unusual on forums like this. For example, you said DD told you that GD's condition, etc. was "none of her business." Did you mean to say, 'none of my business?" Or?? Please do reread your post and clear up the points of confusion (if you come back in). Thank you.