If you can't lock up the things he might contaminate, you will need to throw away anything suspect when you get back. Rather than stress and guess, decide whether you're willing to toss what you cannot sanitize. If not, (if doing that will cost more than an airbnb or motel room near the airport), make an excuse and change the plan. I'm sorry your family put you in this position.

You don't owe anyone your peace of mind about your own home.