1- These days both parents must make their children their priority, not their career. I recommend that she prioritizes raising her children when she has children. This might that sometimes she’ll have to work part-time or not work at all.
2- Australia has some good Muslim communities, so it’s best if she lives close to those communities so her future children can benefit from Islamic programs.
I don’t see any concerns accepting this offer as long as her husband is supportive (and it won’t cause tension between them later because he wants to be upset about it let’s say), and she will prioritize raising righteous children.