Make an IAP in a Restricted Profile

My boy is playing Scribblenauts on an Android 5.0 tablet, under the control of a restricted profile. He's done all the levels, and there is an IAP required to purchase the rest of the levels. Can't do the IAP from within the restricted profile, because no play store access. I've purchased the levels on the parent account, but they don't show up in his restricted profile. How can I get the new levels for him?