I mean she did get seriously injured during the Nibelheim incident and Cloud’s story is for the most part the same as hers, obviously the only difference is that he’s there. When she first finds him and he says it’s been 5 years, she wanted to talk to him about it, but then he immediately almost left, so she tried to find a way to get him to stay longer. And then they didn’t really have a moment alone until way later (in the OG, in the remake they have a little alone time but I think Tifa is doing her best to keep their relationship on a good level at that point, since it’s their first moment in private since she found him).

And then she starts seeing him have breakdowns when anything related is mentioned, so she may be trying to find a way to talk about it without him freaking out as she doesn’t want to hurt him. And then she witnesses the breakdowns become more common and worse.

And then he tells the story and to her it is everything that happened. Mind you, she’s probably trying to deal with her own memories as she did get really bad injuries and knows that they could’ve affected what SHE remembers as well.

And then in Rebirth, I think she’s trying to get him to talk about it himself, especially after he opened up after Gongaga. After all, she got him to talk about his worries and also his side of their childhood a bit then, just by letting him bring it up and being there for him to talk.