This is very scarey and I know just what your going through. The first time my ds was invited to a sleep over I was scared to death...what if he got sick,what if they forgot his meds, what if, what if, what if.   I explained cah as simple as I could saying he had an adrenal disorder and if he got sick or started acting tired and sluggish that they should call me right away. I made sure that they knew he had to have his meds and they were very important. Then I left and went home to worry all night long, and you know what? He was fine. :) Now he spends the night at a few friends houses. They are all good families who make sure he has his meds but he’s also old enough to know when he needs them so that helps. We even let him go out of town for the weekend to a motocross race with his best friend. I just gave them the emergency kit and his meds and they were fine with it. I won’t say I don’t worry but I have to let him be a kid. I’d say my main concern with spending the night is if the parents will give him his shot when he would need it. The family he spent the weekend with had to do shots for fertility problems so I know the dad would be good with it and have no problems. Plus they really do love my child and that makes a big difference. It’s hard but we have to do things like this for our kids to grow. I can tell from your post that your a great mom. Trust your instincts on who you feel safe to leave him with and who you don’t. Just keep all the parents well informed and be accessable the entire time he is gone so you can get to him as soon as you can if there is a problem.