What series (ie 7, 65 etc) do you need to go RIA?
Do you need the 7 or is the 65 fine?
The 65 is to form your own RIA, or be an IAR at someone else's RIA. You are allowed to provide advice for a fee...not sell products or securities.
The 7 is to be a registered rep of a broker/dealer. You are allowed to sell securities, but only provide advice that is incidental to the sale. The 7 must be coupled with the 63 (state license) or the 66 (the 63 and 65 combined).
You sound like you should work for the SEC or FINRA.
Would he need a supervisory license like the 9,10 or 24?
No. Not for an RIA.