go for it. even if it fails miserably, you're only the assistant. so it's all your bro in laws fault. if it is a hit, you can claim it was your expert help that put it over the top. I see no reason not to, since you said you won;'t have to quit your real job. and there is at least a small possibility that it could look good on your resume, either for other brewing positions, or even in non brewing jobs.