If it's built in the 60's likely galvanized water pipes including a main running to the street, lead based paint remediation issues, electrical, code upgrades might be required for sprinkler systems, cast iron sewer that needs to be replaced etc. 

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.  

I was thinking if I had  a mold remediation company gut the place, I might be able to get a new roof, drywall, and flooring,  and get it rentable.I'm wondering if anyone has ever taken on a totally moldy house,  and what their experience was.

Still, demand is high and supply remains low (except luxury rentals, which is in bubble territory right now).BTW, all units in this project sold last year for 2k less than asking across all 3 units and we were very fortunate to have all 3 go under contract right before the snow blitz began.After the sale, we did have to go back and remediate mold in the basement.  

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.

was it remedied?

For example, if there was mold in the house doesn't it mean I don't have to disclose it even though it was re-mediated?

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

I understand, but you need to give me time to remedy.