This is your first house sale, but if you want to be in the business long term, then it won't be your last house, so take the emotion out of it and think if your time and energy would be better spent fighting this guy or looking for and working on new deals to make you way more than you'll spend to get this person out of your life.  

A brand is an emotional corporate image that an audience perceives as who you are, what you aspire to be, and what you promise to them.

So reasonably solid, though hoping to add more value (and increase rents) after a slow rehab cash flowed by income (easy fix when dropping my mortgage payment over $1,600 by moving into this place and selling my primary that I bought off emotion rather than logic).Thanks for the discussion Alex G. and Carson Wilcox !

Working with family can be hazardous to relations, especially if you are not 100% aligned or folks gravitate to the emotional side.I would also ask to see detailed numbers on your sister's property.

Attempting to evaluate the list price after the project is complete is difficult emotionally.

There is reputation risk, mental-emotional-social risk.

I can totally relate to @Jake Andronico and have gone through the same exact emotional rollercoaster.

Take emotion out.

. - it becomes more emotional and can hurt.

She has EMOTIONAL value and you are thinking of FINANCIAL value.You need to offer a compromise.