Yes, it would really be very strange for a man who is (we would assume from the letter) shomer Shabbos and shomer kashrus and whose family frowns on him dating someone non-Jewish to be in this relationship without having had some serious conversations about their potential future as a married couple, how they would relate to his family, what their home life together would look like given their differing religious practices, how they would raise their children, etc.

And if she does convert... Judaism is not a religion to practice in isolation. Keeping Shabbos isn't just about not using your phone for 25 hours, it's also about spending that time with family and community. Is her boyfriend's family/community going to welcome her with open arms and be a replacement for the friends she's already lost, or is she still going to be left on the outer once she converts?

It makes me wonder whether the boyfriend is actually all that observant now, or if she just doesn't spend Shabbos with him as she's not welcome in Jewish community? If not, why not, as a potential convert? And if he keeps kosher, how did it go with bringing him to her family events? Were they able to cater to his dietary needs? Strict kashrus is incredibly hard to cater for, so if he and his family are as observant as she's making out, then would he even have been able to eat anything her family served at all?