I am not a multiples mom, but my coworker announced last Monday that she was pregnant with twins. We were all super excited for her and she was over the moon. I found out today from her BF (the babies father) that she lost one of the babies over the weekend

She has been home for the past two days taking "sick" days, and will definitely be out until Thursday at the earliest, though I don't really expect to see her til next week.
Is there anything I can do, any suggestions anyone has for what to say to her? I feel just awful. I know that she is still carrying one of the babies (though I don't know if it is Baby A or Baby

and that is great, but I don't even know where she would start mourning the loss of the other baby. When I had a miscarriage several years ago, someone bought me an "angel caller" necklace to wear. I loved it and wore it for quite some time, and now it's in a box with several other things I had gathered during that time period...would something like this be appropriate? Or is it better to just keep my mouth shut?
I want her to know I'm here for her but I don't know where to start...
Re: Can I ask for some help? (Warning: loss mentioned)
I've had two losses myself, and the card route is what I had our volunteer group do for my sister last Christmas. It worked very well.
I would simply say you're sorry for her loss and take your cues from her. I think the worst will be people saying "at least you still have one."
9 angels in heaven-3 in my arms and 1 in the NICU
Mono/di twin girls: Josephine born to heaven and Evangeline born Earthside at 25w
A card and possibly a necklace is a nice gesture. If you are comfortable talking about her loss, let her know you are willing to listen if she needs to talk. If she doesn't already know, let her know you have also lost a baby. It is easier to talk to someone who knows what you are feeling than to talk to someone who can't begin to relate.
My twins were originally triplets. I lost Baby C at 7/8 weeks. It really messes with your head. On one hand you feel grief, pain, and confusion, but on the other there is relief that you didn't lose both/more, fear that you still could, and guilt that you feel relief while mourning the loss.