You know what I find shitty...When me and my friend caught his parents smoking, we JOINED IN WITH THEM. We didn't plan to rob them and go blabbing all over town. What the fuck is wrong with those kids, man? I have no right to say "kids these days..." since I myself just turned 20, but shit...If I was in your step-son's shoes, I would have approached you about it and simply asked if I could join in the growing and smoking of the stuff! Instead of creating a bond with you, he goes and tells freinds and they plan to jack your shit? That kid needs his ass kicked and I hope to God that you are the giver of such a beating.
Little fuckin' punks. I would have sent the little bastard packing and told him never to come back too!
Bottom line, though...If you want, finish your grow. But I'd seriously consider NOT growing anymore for a while...6 months or somethin', just to make sure kids ain't blabbing. Kids talk a LOT of shit and if one little book-worm nark catches word, the cops will be at your house with a warrent before you know it. My friend was talking to another friend of ours about his parents smoking pot, and a little nark overheard and told the principle and social services and everything got involved. It was total bullshit.
Just be careful, and if you ever see that little bastard again, kick him right in the balls. I'm not joking either...It's astonishing that he opted to plan to steal your plants and take them for himself instead of just letting you grow and asking you for some pot every now and then. Christ. Lord knows they would have killed the plants off anyways. My uncle has been a smoker for like 20 years and he can't even grow and maintain a marijuana plant...It's got a bit of science to it!