Eventually your child will leave home to lead her own life, but in the meantime she relies on your support.
最终你的孩子将会离开家去过她自己的生活,不过在此期间她依赖你的支持。
For the meantime means for a period of time from now until something else happens.
暂时 Some of her stuff is stored for the meantime with her children. 她的一些东西暂时保存在她的孩子那里。
In the meantime often implies a temporary waiting period or interval before something else happens. It suggests that you're filling a specific gap in time.
Meanwhile can be used in the same way as "in the meantime," but it also serves to introduce a contrasting or parallel action. It simply means "at the same time" without the strong emphasis on a waiting period.