I don't think these people have any siblings, if my sisters didn't do weed i'd definatly give them some alice b toklas brownies, brothers beat the shit out of each other for fun so I don't think someone getting a bit stoned is going to cause much trouble. He should get stoned if you put enough weed in, the reason some people don't get stoned their first time is that they don't inhale properly but obviously that's not a problem eating it. I'd try them first and only give him a small dose though, you don't want him freaking out.