Google search results are quite deceptive, because they depend on a lot of factors. For example, your location might make a difference. And if you are logged in to Google, your search habits will have been tracked and Google will give each person different results based on their search history. That is, Google's algorithms are making decisions on what to show you based on what they think you are interested in.
And what does being on page one mean? For a specific key word or phrase? Or for the name of the company? (If their site is about cars, their site will never come op on page one if you Google something like 'garden gnomes', for example.) It's a very wooly area, so you need to set some parameters for it to mean anything. E.g. your goal may be to get their site to come up on P1 of Google when you type their company name into Google. Make sure they are logged in to their Google account first, and get them to visit the site a lot, too!