Heather, Get all of that anger and frustration out of your system tonight. I want you to get a good night's sleep and be ready for tomorrow. In other words, be civil. Why be civil? I don't want him to take it out on your daughter and go over the top and do something stupid that will cause her additional emotional stress. You are going to have to find a way to remain cool and calm when he arrives tomorrow.
I think that your h looks at the situation at home as you are being over protective and by being that way, poisoning the thinking of your daughters against him. This is only a guess as to what he's thinking.
Well, I hate to say this...but he's going to be mucking things up quite a bit because he knows it's the only way to get what he wants.
Unfortunately because you don't have any legal documentation, you can't demand that he provide you with the results of a drug test. However, you'll be able to tell from his actions tomorrow if he is high. If he's high, the minute that child is put in his car and he pulls out on the highway, call 911 and have him picked up.
Whatever you do, please try not to get into a verbal fighting match tomorrow. You don't want this type of thing going on in the presence of your daughter. It will not bode well for her if you do.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.