Perhaps "sending her back to the mainland" meant the child wouldn't be able to eat at McDonald's or go to an English-language kindergarten any more, but for a small family who "just want the whole family to be together, never mind where," such things are really not important.
「回大陸」或許意味孩子以後沒有麥當勞可吃，沒有美語幼兒園可上，但對一個「只要全家在一起，去哪裡都好」的小家庭來說，他們並不在意。