OK, so your friend got a little too high. Not the end of the world. You've dealt with high people before. They're not so bad. Usually they just go off in their own little corner and laugh at cat videos. Or they talk about existence in a way that only they understand. It's all gonna be fine. You've taken care of too-drunk people before, what could be much different? This is gonna be no sweat... Really.
1. Denial.
They’re not really that high, are they? OK, so they look like they’re seeing aliens, they almost broke the sliding glass door, but they’re really fine… Right?
2. Anger.
Not necessarily at them, but at yourself for allowing this. You shouldn’t have let them have the other half of that edible. “But I don’t feel anything,” they said. Famous last words. You gave them the other half. Tragic mistake.
3. Bargaining.
“I promise the police are not out to get you. Here, look, I’ll give you some chips if you come down from there. OK, do you want money, then? Please, the chandelier is really not as sturdy as it looks.”
4. Depression.
Yup, you’re in this for the next 6+ hours. There’s no stopping it now. What do you do now? Get crayons? Put on a movie? It all seems so useless.
5. Acceptance.
Alright, it’s true. They’re way too high and out of control. But, you’re level-headed enough, and you’re going to get both of you through this.
Regardless of outcome, they’re still your good friend, and you’re going to get them through this high. Besides -- you’ll be able to laugh about it when it’s all over. (As long as they don’t rip the chandelier out of the ceiling.)