The only person I genuinely want to be held by is a romantic partner, and if I don’t have a partner, I don’t feel any touch-starvation. What advice can I give her? I really want to be compassionate and helpful, even if I can’t personally relate

i'm similar; it's not something I've ever had a need for and it is kind of hard for me to put myself in a mindset that needs it.

It's obviously not the same but if she has the money for regular massages/hair cuts (with shampooing done by a pro), those can make you feel a bit less like you live in a bubble. Beyond that...talking to her friends about it is exactly right; she may have friends who feel the same way!

Just showing you are listening and empathize with her is already doing a lot. “I’m sorry you’re suffering. Sometimes culture shock creeps up on us in ways we can’t predict. I hope you find a way to get that need fulfilled while you’re here (assuming she’s here temporarily). Otherwise, what about..

Touching animals for sure. If she can't have one, even a small pet like a hamster, then going to animal cafes might be the only option. I wonder if there's service animal training programs to volunteer for in Osaka.