There is no appropriate platform for a referral matrix type of platform even if it's promoting the use of Bitcoin, and I don't think any reputable members will help you to promote your platform.
You are absolutely right, I did not understand what the matrix he wants to promote has to do with bitcoin? And why does he want to promote it in the bitcoin forum in the first place?
This kind of matrix is actually a Ponzi scheme based on the referral system done by the old subscribers and the subscribers below them, so I don't know what they need to run a promotional campaign here on the bitcoin forum?