I take a comment about him being the one who's taking it hard is inappropriate? But seriously you tried right? Maybe a short spell inside will make him realise how much he prefers it outside, I really do like to think everyone can change.
I hope you learned your lesson, never ever ever let a cop into your (or any one else's) house
they can enter if they have a warrant, in which case they will probably break down the door at 3am
otherwise, you GO OUTSIDE to talk to them with the door closed behind you, or tell them through the door (without opening it) that you don't want to speak to them/ have nothing to say to them
Those arent bad choices. Now then, you're taking it hard because you responsible for him getting locked up but the reality is that he probably would have gotten caught at one point or another whether you were around or not. Dont you have any other friends besides him who can help you get through this?
It's tough when something happens to someone you care about that's out of your control. But really, shouldn't he get warnings or something? If he's been on probation for six months and this his first infraction and it's for something stupid like missing curfew they shouldn't waste their money putting him back in jail for something stupid like that.
Don't be too hard on yourself. And yes you're way deeper into this than you think you are.