The South Korean is going through contract talks with the club.
Spurs want to ensure the forward stays beyond this season.
While he still has three years on his contract, the club wants to ensure he spends his entire prime at the club.
Son has signed with the sports division of Hollywood talent agency CAA Base.
Mourinho is also represented by the agency for his commercial interests.
"That is not my job, I don't care about who represents players, I just care about what players give me on the pitch and nothing to do with that," Mourinho told reporters.
"Sonny's agency represents me on my image rights and commercial work outside my football job and that is it. Nothing more than that. The majority of my players I don't even know who their agents are.
"An impact on Sonny's future, I don't know. I can say at a commercial level it will be a big impact because it is a worldwide, very, very important agency."