I used to be on the SANDS forum OP, and I don't want to say anything negative about a place where I received a lot of help and made some good friends.
But it's a place that runs on high emotion and what you describe is a normal thing for many parents who use the forum.
It's never been my way, I suppose you could say I prefer a more traditional way to grieve and remember, and I found it quite stressful on SANDS because the norm on there often seemed to be everything you described and more.
Which is okay if that's what you want, but sometimes there was a lot of pressure to fit in and do the same, and one person in particular accused me of being cold and not caring as much for my children because I wasn't doing all that. I've seen that accusation thrown at a few people by that same person during my time on that forum, and it does make you feel like you aren't grieving properly and ought to be doing more, and doing it more publicly.
I'm wondering if your friend looks so unhappy in the photo's she posts because it's not really what she wants, but she's caught up in a group of people who do, and she feels it's what's expected of her.
SANDS was a big help to me in my early days, and I wouldn't want to put anybody off using the forum if, god forbid, they lose a child. I've made four lovely friends by using SANDS, who I speak to on a daily basis online, and you can get a lot of help and advice. But ultimately I felt more able to grieve in my own way once I left and didn't see on a daily basis the things other people were doing differently to me.
I will say that I don't understand their way any more than they seemed to understand mine. Where it brings some people comfort, I know it would cause me a lot of pain. But you never forget your lost child or children, mine will be a part of me forever. I'll always be their mother, they are in my life daily, in the way I chose to live it, in the things I do to honour their memory.
I was speaking about it recently and said that one of the reasons I went back to college to get my degree is because I would have wanted them to get theirs, because I want DS to get his.
I would have wanted them to follow their dreams and ambitions, and eventually this degree will allow me to follow mine, and so in a way stand tribute to the dreams and ambitions they never got the chance to follow. And hopefully it's my way to inspire DS to know what his are, and follow them. It's not a party or a cake on Facebook, but it's a daily thing I do because they can't.
What I'm saying is, maybe this is what your friend wants to do, which is fine, but maybe it's just that she hasn't found her own way yet and that's why she looks unhappy.
But whatever her way is, she's doing it because her child will always, always be a big part of her life on a daily basis, and she's probably doing all sorts of things, big and small, to remember them. Not just this birthday party stuff but so much more that you don't see.
And it's hard, and we know people are looking at us and judging us, some people thinking they would never be able to cope with what we have had to cope with, others thinking they would never do what we do.
What matters is that people support us in the way we cope best, in the best way they can. If you feel you can't wish her child happy birthday, that's fine. I usually go with something else as well, such as "thinking of you on X's birthday" or "I hope you have a gentle day" because to most parents having someone use their child's name or being told someone is thinking of you and haven't forgotten your child is the most important thing.
Not saying anything at all is fine too, if you really feel you can't, because at least you're not being dishonest or saying they are doing the wrong thing, you're leaving them be to mark the day as they see fit.