I once had a conversation with a girl who's father had cancer, but he didn't want to use medical marijuana because he was afraid it would set a bad example for the rest of his kids. It was really sad to hear her talk about this because this girl wasn't thinking about marijuana as a party drug, but as a serious medicine to help her father. I think if you sit your kids down and just explain to them that it's for your health they will understand. Your older ones might have already had this discussion with their friends but afraid to bring it up.

Hopefully your doctor will be understanding, but they might not know much about medical marijuana so I would recommend printing copies of Prop 215 and SB420 out for them to read. This way, they will know exactly what the law says about it so they don't have to worry about loosing their license or getting in trouble.

Here are both of those bills:
Prop 215
SB420