The administrative fees charged by a regional center are typically governed by the regional center’s securities documents and business plan to cover some of the costs of putting the project together, to offset some of the regional centers fees for legal documents, marketing and other expenses and market driven forces, i.e. the need to be competitive in the EB-5 marketplace.
Since your friend is not part of a regional center, more likely a market promotor for the regional center, your friend is unable to offer you any administrative fees which are charged and collected by the regional center. Your friend may hire and pay you wages for your services but if you are paid per transaction, i.e. from an administration fee accompanying an investment, you may be acting as a broker and would need a license.