Silent partner has offered us a loan. He has no control of the Corp, and he does not exist in our papers, etc.

My partner and I set up an LLC to start our company. Then we asked for a loan from a friend of ours who asked to be paid back in full and wants a third of the company. He was never added to our llc, etc. We wrote a notarized letter saying that he borrowed us cash and that he had a third of the company and we had to pay him back in full. 1 year later, he was paid back in full by check. Will he have a say in business legally if he’s not a member of the llc? The explanation is that he is invoking a 51% controlling interest on us because we “break our deal” by not paying tax on time because of the hard times of the coronavirus.