My little brother saw The last Excorcism and now he's completely traumatized. ?

I was watching it with my boyfriend last Saturday night and my brother (8 years old) asked could he watch it, I said no because it would be 2 scary 4 him. When we finish watching it my bf and I head upstairs 4 a bit. While I was upstairs my brother put it on and watched the whole thing. After he was petrified. He wouldn't go to bed and he was crying all night. It's been 4 days and he's still freaked out. He can't sleep on his own and he wets the bed. I've tried 2 tell him it's just a movie but he won't listen. I need to get him to be over it by the time my parents come back from holidays on Friday but I don't know how. Please help