help. we're dogsitting a 1-year-old yorkie

who has not been fixed yet. he is making life miserable for my 10-year-old chihuahua, and the 3 humans in this small apartment. if he is not trying to hump my dog, he is whining, barking, wailing and crying to get at him. either does not know or does not care that he's after another male.
it was funny at first.
https://www.facebook.com/photo.php?v=10154163383850716&set=vb.538110715&type=2&theater

that was a couple days ago. any suggestions? he's here until Monday.
thanks DU!