Sounds like a cool mum & nan. I have never heard of any effects from smelling the weed, but again cool for thinking abot the precaution. It would probably be best if your brother & sister never found out depending on age etc as its a lot of responsibility to ask them not to talk about it. If they were to get in the position of getting hold of some & ate it that might have some effects also I get like a nettle rash on my arms if brushed by resin while working on them.