You can try a 1031 exchange to avoid the capitol gains. 

If he sells and uses the proceeds as a 1031 exchange, can we both go into a purchase together as in mortgage/deed?

I will file a 1031 exchange with all the properties.

@Isaiah WrightI haven't done a seller financed deal yet, but I've been doing obsessive research in the past couple weeks.This pros of this purchasing strategy are that the terms are negotiable, and you can get away with putting low or no money down in exchange for a favorable interest rate and sale price to the owner.

Value-add operators and their investors are willing to accept lower returns in exchange for lower risk. 

I had a discussion with the Asset Exchange Strategies who was also able to offer some guidance. 

You can do a 1031 exchange to an Austin location.

You would 1031 the land sale into other assets (not the development) and contribute the land you do not sell to the entity that will develop the property in exchange for membership interest.

But unless this is part of a longer term plan that includes 1031 exchanges until death (or another TRUE tax "savings" strategy like an Opportunity Zone) wouldn't the investor be paying real money (in the form of increased taxation when moving from Passive investor to Active Investor-passive gains vs. earned income) in exchange for tax DEFERRAL....Eventually the tax benefit known as depreciation needs to be re-captured.

only one partner in the TIC 1031 exchanges their portion, while the other partner wishes to take profits on their portion.It's a 50% 50% Tenant in common partnershipThanks