Boyfriend with poison oak?

My boyfriend got poison oak the other day. He claimed he didn't get it when he was younger, but it's poison oak for sure. He had it bad in one spot on his arm but he started itching it and now it's EVERYWHERE. I'm getting him some calamine lotion today, but is there anything else I can do at home? Something to remove the oil from his skin and make him stop itching? 'Cause he won't no matter what I say. What can we do?