You need more time. 10 months isn’t enough to get over culture shock and home sickness when you’re living abroad long term or indefinitely.
Go to the pharmacy and get some vitamin D. Back in Canada I used to get it as a spray. It helps a lot with seasonal depression.
And remember, leaving where you are doesn’t mean you have to return home. There are other countries to explore.
It entirely depends on how long she’s supposed to be there for. There are stages to adjustment and culture shock. If it’s one year, the first three months will be the hardest. If it’s three years, the first year could be difficult. It’s all in relation to the amount of time you’re expected to be in a location.
Not to say she shouldn’t go, but there’s always a period of questioning and turmoil where you don’t quite fit in. If she feels it’s what’s best for her then of course she should go. I ain’t her keeper.