This is a discussion on Is it possible to share apps? If so, how? within the iOS Apps forums, part of the iPod, iPhone, iPad Forum category; I have signed into Home Sharing using my apple id on my son's machine and mine.
All we seem to share, is music - no ...
So...if we both want the same app, we both have to buy it?
But let me make sure I understand 100% of what you're saying. You guys have home sharing turned on and want to share apps from an iOS device to another iOS device on a different Apple account?
If you plug your iOS device into your PC/Mac you can toggle sync apps and it will put them on your PC/Mac and you can download them to the other iOS device as long as it is running with the same account.
If all devices, a maximum of six, belong to one iTunes account, all of them can share apps. Unfortunately it will mean that if your son's device is reset to your account you may have to share the password and suffer his expenses... :)