Also, as said above, the houses you're buying for BRRRR are usually in awful shape and won't qualify for a regular loan. cash or equivalent up front is the most efficient way.  

I’m in business so I expect proper communication of project progression but I’m not getting it from my general contractor.

i agree with Robert above, hopefully just communication and kindness helps.

Was anything communicated during rehab when budgets were being exceeded?  

Unsure what you mean about efficiency.

To make BRRRR work, you have to get a worthwhile property at a discount, and rehab it efficiently and economically.

Sounds like a great plan in my research thus far.. but am wondering what the most efficient use of those funds might be or if this roughly a good entry point.

What is the best way for this person to get the most efficient use of his money?

What is the best way to communicate with your team and what options do I have?

There is a whole market out there where folks purchase properties and resell them at a premium via seller-financing or lease-option to folks that wouldn't qualify for traditional lending.If you're really interested, you might as well shoot out your lowball offer or a letter expressing your interest to purchase at a lower price and asking for further communication.