Sorry to be honest but her changes that he could get a Tourist visa is really low, even more if she will not be the one paying for everything, if she does not have stronger ties to her country. Single, young women from South America normally are high risk because a lot overstayed their visas.
Looks like you both are looking for a “testing dating” visa. There it’s not such thing.
I advise you, if you work from home or can find a job like this, to before applying for any immigration visa, spend a lot of time together.
I’m not saying that this is your case but unfortunately a lot of people rush the decision to apply for a immigration visa, because they want to be together as soon as possible (and could not get any non-immigrant visa), and this is not just frustrating but also really expensive. Immigration is a long term commitment!
Mexico is also close and she can move closer. The F1 visa is just a excuse to be together because she can study English in so many other places.
Other things that you can do to help your relationship is to learn about US immigration and to learn Spanish (if you still don’t speak!).
Good luck in your love journey!