There is a high demand in China for native English speakers to teach their kids. But are they the best for the job? There are pros and cons to having a native speaker for a teacher, and some of these do depend on whether the native speaker happens to be bilingual.
Obviously a native speaker knows their language better than a second language learner can. Their pronunciation is usually very good, and they will instinctively be able to spot mistakes in learners. However their are a few cons.
The first is that if the native speaker is not bilingual, they will not be able to adequately explain many concepts. Or they will, but in an inefficient way.
The second is that sometimes someone who has struggled with learning the language, who has taken the path you want to take, can be better at explaining things in some situations. This is because they have had to think their way out of this problem themselves. For example, while a native language speaker can instinctively realise when something is wrong or right, they may not be able to explain it other than by saying ‘it just is,’ but someone who has learned the language may be able to explain it better.
I think the best solution is to combine both approaches, having a native speaker and a second language learner as teachers would give you the best of both worlds.