How can I explain proceeds from a stock sale through combined sources?

I am trying to determine whether the following source-of-funds/path-of-funds structure would be acceptable for an EB-5 petition and how to present it to USCIS.

I have a Bank of America account where my salary is regularly deposited. The account also has some relatively small deposits from other sources, along with normal expenses and withdrawals. I transferred funds from this BofA account to my Chase account, which also received funds from my elder brother. The funds from my salary and my brother’s deposits were subsequently commingled in the Chase account and used to purchase stocks through Charles Schwab.

The Schwab stocks were later sold, and the proceeds were transferred to my wife, the EB-5 investor, and are being used toward her EB-5 investment.

Is this type of combined funding source potentially acceptable for EB-5 if the complete transaction trail can be documented? How should the funds be characterized—e.g., my salary/personal savings, my brother’s funds, or stock-sale proceeds? Since the funds used to purchase the stocks were mixed, what is the appropriate way to establish the source and path of the specific funds that ultimately generated the Schwab stock-sale proceeds?

What documentation would typically be provided to USCIS to establish the complete trail from BofA salary deposits → Chase (including brother’s deposits) → Charles Schwab stock purchase → stock sale → transfer to wife → EB-5 investment?

Would it be necessary to separately document the lawful source of my brother’s funds, even if the EB-5 capital ultimately came from stock sale proceeds?