I am having the hardest time house-breaking my puppy.

My dog had two puppies 10 weeks ago. One went to live with his forever family last week. The other is still hanging with us until we find a suitable home for him.

They were doing a good job potty training together and the remaining puppy was doing great until yesterday. I take him out on a consistent basis, every 1-2 hours or when he's showing signs of needing to go. He's kennel trained (he won't go in his kennel at all). I praise him with treats when he goes outside and scold him when he goes inside. Aside from the rug, which needs a deep clean at this point, the floors are clean. I clean with enzyme cleaner and disinfectant after he goes to try to get rid of the smell.

Now he has started biting us when he gets in trouble. I am at a loss on what to do. I've never had a puppy be so defiant. Is is maybe related to his brother being gone?

Taking all and any tips or tricks.