For homeowners, how to buy this falling apart property?

Ok this is a lil ask for help to you people that own their own house and property;;; Ok, a couple years ago my nieghbor died, and her house is unlivable (the roof is caving in, and the house itself is slipping off the foundation), however, her son (which is now the owner) has basically abandoned the house and our guess is that in a couple more years the house will fall in on itself. Which means that the house will go under condemn(sp?) ok when that happens I am thinking about pulling it out of condemn and buying the property and still let them tear it down, but since it will be my property I want to put a kit house on it. Ok the problem is I really havent a clue about exactly what I am doing and I cannot find any help concerning mortgage, finances, etc or anything on the web and nobody in my family knows nothing about it either (they have rented their whole life and paycheck to paycheck). Any advice that might help?