My brother insisted on doing work on one of our apartments himself to rehab the unit that rents for about $1200/month.

I will insist on a quick walk-through with my contractor friend, and if that is not allowed, I will walk away.

Your call.I have been hired by sellers to list/sell/handle the transaction when the buyer looked like they would be someone the sellers had a previous relationship with....I told the sellers they could make me the "bad guy" if something came up the sellers wanted done but were hesitant to insist on because they knew (or had a previous marriage with) the buyer.Best to you! 

If so I would insist that the other owner get his owner water service.  

It looks like I need to have a wall mounted air handler replaced in a condo and I am wondering if someone knows a good HVAC contractor who does partial replacement and not insists on selling complete systems.

Back when I was brokering commercial real estate 100 years ago I had a deal on a small office building fall through when during the walk thru just prior to closing the buyer insisted on checking the candy vending machine and verbally to;d us and sent us a follow up letter informing us that he wasn’t going to close because the Baby Ruth’s in the candy machine were stale.  

If seller is willing to finance 20%, is he willing to accept a subordinated lien or is he insisting on a first lien?

@Bonnie LowI own one right here in Sisters I was scarred to go to far away for my first one. 

Our internal firm policy (this is not a law, just our rule) that anytime you are dealing with unaccredited investors, more than 5 investors, or raising more than $500,000 we insist you use a PPM.

So they wrote a letter to the landlord insisting on a rent reduction of $100 based on what they called "rent discrepancy".