The biggest problem for a child to stay with chess is studying chess everyday at home. Because they don't have anyone to ask at home when they have questions, they stop studying at home at all. Learning chess once a week is not enough. We learn Math everyday at school. We learn English everyday. We learn most subjects everyday. Chess is the same. You have to study it everyday. If you only touch chess once a week, you can't improve much. If you can't improve, then slowly you will lose interest. That's one reason we assign a lot of homework, so at least you have the opportunity to do a few problems everyday. We also suggest your child to play online everyday, and to go to tournaments if they are ready.
That's also the reason I am creating a new video course to mitigate the problem. We will work on a book together. If your child hit upon any problem, s/he can ask. I will record a video every week to answer questions. It's an ongoing course. My initial commitment is 2 years.
More information can be seen on:
There is a demo video there. I will record a few more in Feb.