9 week old puppy for first time owners, has parvo and kennel cough, can’t take outside

My boyfriend and I just adopted this 9 week old lab mix. We’re both obviously very new to this and im going to be the one around him most of the time because of my boyfriend’s job. Apparently, when we adopted him, they told us he has parvo and kennel cough. They only gave us meds for the kennel cough. He has his necessary vaccines except for rabies (cuz he’s too young).

The thing is, we want to start training him, potty training, basic commands and being comfortable with the cage. The thing is, we can’t do that the traditional way with treats because of his parvo. We have carpets and we’re worried about him peeing everywhere (which he has already started doing). I can’t leave him alone without being afraid that he’ll go to the bathroom in a bad place or chew on something or him crying because he’s in his cage. We want to be as gentle as possible when it comes to raising him. Any advice would be greatly appreciated.