If this will be a long term relationship that will grow, it might make sense to create an LLC, combine your capital and be partners. You will both be capital partners and share P/L. You can be the managing partner which can provide you a higher payout of gains for that role to cover your time and effort. That way you both get a K1 at end of year. This will have a cost over and above a simple account where he pays you to trade, but that would require a 1099 and that expense might not be deductible and might subject you to registration in your state.
If you want to consider #3 and moving your relationship to Lightspeed, I'm happy to discuss this. #3 is the cleanest options.
Bob