^
Based on their schedules, it wouldn't surprise me if they were somewhat limited in how much/how frequently they were able to keep in touch (eg. probably would have mostly stuck to LINE/e-mails/text messaging and the like). And even then, talking with her online or even seeing her and doing stuff like going out for a meal is one thing, but actually seeing her back performing on stage would/could have had much more of a significant emotional impact (after all, many of them admit they grew up watching her before they joined H!P).