Why would they come after google? A parent can make nearly any transactions for the child. And 17 year olds can take jobs, so even giving him a "job" to pay him trough that probably only would interest the tax guys ("Why are you paying some guy in germany 10k an hour" "Because we don't want to wait to long to transfer all the money" probably is problematic).
If it is a problem with US law, both google and paypal have companies in the EU that could handle that.