Watching my sister's puppy- worried about Henry

Henry can be snarky with other dogs who get in his face and are bouncy. And a five-month-old chihuahua is bound to be bouncy and I worry that she won't back down, which will only incite Henry.

He wouldn't be out for blood, or anything, but a snark-fest is something I'd like to avoid.

Should I just keep them on crate rotation the whole time? It's only for 2 nights.