Friend on the spectrum.

Hi

i am not on the spectrum myself but my friend is and I’ve began to learn about how she sees the world. I know some things she has to do like sit back centre in the cinema for sound. And sit in a certain place when eating. But I have noticed that most of the time I’ve known her she’s become obsessed with America. And a trip to Canada made it worse. And she wants to go meet a stranger there and I’m really concerned as everyone who tells her to not do it she basically retaliates and strops a little. It just makes me feel awkward as I try let her talk about it because it makes her happy but I just think she talks about it a bit too much as it’s like every other sentence is to do with America and how much she hates where she lives and how she wants to live there. Its baffled me for ages and I was wondering if anyone has been in a similar situation and could maybe give me advice on how I can tell her she talks about it too much. I don’t want to make my friend sad. Also she has high functioning autism so I’m not sure if it’s that or anything. Thanks.