Introduce him to the merits of a professional photographers contract and give a few references, maybe he'll see it differently.
Nonsense, capture fees are a very common way for professional photographers to work. All the second shooters I have ever used have been capture fee only employed, I have been capture fee employed on many occasions. You can choose to not do it, that is fine, but many pros do work like that.
Think of it like this, I get a job, I employ a second shooter, I am in charge of everything, lighting, posing etc etc, why should the second shooter have any rights over those images? It is not an example of their work, it is an illustration of mine.
Or another, many many pros have "assistants" often shooting with remote cameras, they do not (very rarely) get the image credit, it is the primary photographer.
Or another, an event organizer, they have the rights to the event, they can employ stills and video teams that have no rights to the images they capture, it is a very common scenario.
Or another, many agency employed photographers contract image making, that is they tell a photographer to go and take a specific image. The agency has all rights to those images and the photographer has none, they were contracted on a no rights basis.
See all the Getty Image/AFP credits on images? Many of those are owned by the agency not just managed by it, often you will see ©Fred Blogs/Getty Images, these normally have shared copyright but are licensed through the agency.
People talk a lot of rubbish about copyrights, a contract can, and often does, override any rights you have as the capturing agent to use those images, and that is not, necessarily, a bad thing.