I'm sorry, I didn't mean to overstep. I didn't think you should cut her off because she drinks milk, but because from the way I read your initial comment it seemed they had brought meat into your house after it was clear you had established a no meat rule, as part of a larger pattern of disregarding your boundaries -- perhaps a projection of my own experiences.
I hope you and your mom have a good time together when she comes.
This video got me about a year ago. Nothing super graphic, not at a slaughterhouse, not even any abuse. But the "simple" act of taking a newborn child away from their mother completely shattered any remaining dissonance I had about going vegan, personally.
I will echo the other commenters suggestion to get some vegan creamers. Honestly, it may be worth considering cutting them off if they can't follow your rules in your own residence. There's plenty of food to eat that isn't meat (obviously); there's no excuse for them having meat delivered. If they can't go one week (not sure how long they're staying) without meat/dairy in your house, then they honestly don't care about your feelings.
I would ask them what foods they would prefer -- give them options like tofu, different beans, lentils, edamame, etc. Maybe make a soup with their chosen legume.
I would encourage you to compromise and """allow""" them to eat non vegan if you go to a restaurant. I understand this is really distressing, but with some people it can be helpful to focus on one goal at a time (e.g. no animal products in your residence).
I've been doing this with my Kindle, and it works well too. I saw this video earlier and I think I'll still do it because (1) I hate the popup every time I go to the library that asks me to connect to WiFi/login to account, and (2) Koreader features seem really nice. Still though, not enough of a big deal to make me do it today :P
I used bottles for a year or two and just switched to Faugus Launcher. Seems a lot more reliable at opening/closing Battle.net for whatever reason.