I would definitely give her space. I'm sure it's hard, especially since they were trying.
I had something similar happen to me recently:
Last month DH and I met up with one of my best friends and her husband to go out in Myrtle Beach. Her DH was being really quiet and stand offish all night, but I didn't think much of it. I just thought he was tired or something.
Toward the end of the night, my friend pulled me aside and said, "Hey I'm sorry my husband is acting so strangely tonight but we've been trying to conceive for a while. We went to a fertility doctor last week. Right before we came
out to meet up with you, he got the message from the doctor saying he was infertile. His cancer he had when he was a child wiped out any hope of him ever being able to have kids."
I felt sooooooooo terrible after I'd just been flaunting my big preggo belly all over the place. I wish she had warned me before they arrived via text or something.
It's just one of those things. :-/ DH and I weren't trying either. It was a surprise for us. And then here we were talking about how unexpected it was to a couple who desperately wanted to be in our situation.
It's so heartbreaking in situations like these, and I can't even imagine how it must feel. ...But miracles happen every day. :)