There is an alternative for the oversea insurance and much cheaper.
You can travel insurance annual plan. The coverage, in particular the medical coverage which it is more important, does not differ much. There is also coverage for loss of property and change of travel plan.
The plan covers upto 90 days every time the kid leaves Hong Kong. Depending on the travel plan, your kid won't stay longer than 90 days between each break. It costs about $1400.