I know this is a broad question but me and my brother have agreed to use this money purely for investing and to help us in our goal with financial freedom and to set our mother up for success.

My personal preference is investing in real estate and there is a high probability that many in this forum will say the same purely because this is a real estate investor focused forum. 

I have a clear vision of who I want  to become within the next couple of years, I have pure motives and will always honors those who helped me rise. 

Could just be the back up battery.. they sometimes cause a hummmmm

I would recommend reading the online magazine, Baton Rouge Business Report to get a pulse on the local enonomy.And that was pure media hype over potentially losing a home game for LSU.

The batteries and perceived maintenance is what scares people, and for good reason.

If you stay at your parents and just try to buy a pure rental, you will need 20-25% down payment which will add limitations to where you purchase.

Based purely on my experience working with investors. 

Am I correct that my LLC could partner with my SDIRA if it were a purely passive investment, like a turnkey property managed by pm that I put no sweat equity in?

I have pulled significant amount of equity out of pure buy and hold with no renovations as well, usually you just need to wait longer for the principal pay down and market appreciation to build up equity into the deal.