That sounds like a terrible way to lose a pet, please extend my sympathies to your friend
As to whether your dog can get sick from anything in her house, I won't say no. Your dog can get sick going for a walk around the block, there are microbes everywhere just looking to set up shop
However, I wouldn't be terribly concerned if it were my dog going in.
"He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion."