Than the breeding of her Yorkie.....
I feel very bad for you, I know you have a heart. And you are trying to do the right thing......I got an idea.....let him read all the recent articles about delivering Yorkies.....quite frankly, they scared the crap out of me and I tell you.....I would spay her before I would allow him to use a bigger male on her and her being so young....
It is a shame.....sounds like he THINKS he is the boss at your house....