Official word right now is,covid = 1 dose.
Thus why my sentence begins with "I personally have the impression". I agree that having contracted Covid gives you a similar, if not identical immunity to having one does of the vaccine. I have no data, I have no expertise, it's simply my impression based on reading documents, articles and medical journals.
That being said, I would also think to "normalize" things, if for whatever reason they decide it's the best idea to have vaccine passports (For international travel sure, regulate the people not from your country all you want, but don't do this nationally to our own population) then proof of two vaccines would be required for him to travel to Europe, therefore he would have to get a second shot even if he was infected with Covid.