Any remedy yet?

It seems like even investors don't want to mess with mold remediation.  

I don't mind doing small projects exposed to it because limited exposure is relatively safe, but as much as you have should have some real remediation.

It may not be difficult to remedy but will come at a cost.

If he is willing to release his interest in the property it shouldn't be much of an issue and something your attorney can remedy with relative ease.If the brother wants more money or altogether refuses to play along it can be difficult - and maybe impossible - to get the deal done.

My biggest concern is to buy a property and then have a major issue occur and not have the cash available immediately to remedy the problem.

Let's assume: 6 tenant turns a year$300/turn lease-up fee$700 rehab per turn3 weeks total vacancy per turn$500/unit remedial maintenance per yearIf I include the above factors into the spreadsheet, I get the following:I've talked to a few 4-plex owners and reality is closer to 2% than 9%, unless you bought the property during the crash at a very low price, which is much less than what you would pay today.Questions/Comments On Your Proposed Purchase Ignore "rules".

It might be to your benefit to do a little research on the property and what remedies your municipality might have--sometimes you can even acquire an adjacent property for little to no money.  

April is remediation for water, freeze, fire, mold and smoke damage.

Contact them too and ask what remedies are available, they may be able to guide you to city resource for repairs of this caliber.