I don't know if you really have OCD or you were joking, but either way, the cure is to FACE YOUR FEARS. I say let him borrow it, even though you may be a nervous wreck. And when he returns it and it's just fine, you'll see that you had nothing to worry about. This may actually help you! I have certain fears/OCD type behavior myself, but when I overcome that fear and suffer through it, I find that I got through it fine and it really wasn't as bad as I thought. I think your anxiety is worse than the actual event. Am I making any sense here So basically, I say, let your BIL borrow your pup. After all, they are your family, and pup is just a posession.