We have completely gutted the house besides the bedrooms and trying to finish up so that we can put it on the market in 2-3 weeks.

AAS in Electrical Engineering Technology, AAS in Mechanical Engineering Technology, and finishing BS in Engineering Technology.

There are either calls complaining of our tenant or our tenant complaining about neighboring tenants too often (mostly late noise but parking, etc.). 

He’s late consistently sends his check about a month sometimes even two months late.

My question is, could he be liable for finishing out any of the rehab?

My aunt and uncle lived in one side of a duplex and rented the other back in the late 1970's.

Probably not.Of course, this would be different if you were looking for finishing money and the broker offered you something that made sense with an expectation to make it back after the sale.

Welcome to BP @Elijah Voigt There are a few local meetups that have been set up lately and of course the SJREI meetup that is weekly. 

I just finished my real estate courses, and I can not wait to hang my license, probably in the city of Downey.

I have a duplex in downtown Asheville, NC that I have owned for 10 years and recently finished rehabbing the upstairs part of it and have it for rent.