I live close by.

Get into sales or a high income industry.

Then the Tenant will see it, close the account, and disappear.Best option is to turn it over to collections.

I will honor my agreement of refinancing or doing a loan assumption as soon as I'm able (I've been trying excessively over the past decade), however if he does force a sale, can I tack on the fact that I've paid all expenses including the mortgage for the past now 13 years to demand he reimburse me half, or is he entitled to half the equity and I'm just screwed out of everything I've put into the house?

. - upon sale, the property tax will be increased to be based off current market value (~1.1% of current value).

I will be in zip code 46220 and 46240 if there is anything close please let me know.

My question is how will a house sale affect his retirement and selling me the house at a discount will affect me?

Price is fairly low for the upside and it does have $300K in a perpetual fund  for when sales stop. 

2) Trying to get a better price with a fast closing.3) Property needs work and can't get a mortgage on it.

A comp based appraisal is going to be based on comparable sales, so yes.