I would imagine he would do the same thing I do when I take my son into a public bathroom. Which is the same thing I do when I take him into the bathroom at home. Men's bathrooms have toilets and sinks... that's all a little girl needs, right? Help with whatever your kiddo needs help with depending on age and ability. It's not a big deal, truly. Glad your husband is thinking ahead - but it's really nothing to worry about.