Awkward to say that you make your grown son whole... but alrighty then. You gotta put your foot down. Gotta try the polite way first, if that doesn't work then do it the harder way. I have problems with other people using my kitchen utensils and things, luckily I haven't had to shoo anyone away from then in a year or so. But I would be upset if she was like "oh I'm coming over to cook in your kitchen." It would be different if she called and asked if you guys had eaten, and if you didn't she would like to bring you something she made. Thats a bit more easy to handle than being bombarded. In my opinion. As for the pill things, thats on her cus thats illegal, and if she gets caught or whatever thats on her. But if it feels like she's too much you need to vent it out. No other way to go about it.