I would love some feedback on this potential deal!

[Josh Helms]

OK so this is a lot crazier than anything I have done so far - which is not much by the way.  I have one investment property and am in the process of renting out my current house which would give me 2 rentals so far.  

So here is the deal.  There is a great trac of land near me in a very desirable area.  It is 10 acres directly adjacent to other properties with nice houses that have sold in the millions recently.  The problem is there is a cabin on the building site that is absolutely terrible.  It has to be town down although I am not sure the owner thinks so since he advertised it with the cabin.  Here is where it gets weird. 

At the bottom of the property is a manufactured home where his elderly parents live.  Now, he has expressed giving a price reduction for letting them live there until they die. I know there is a term for this I just can't think of it now.  So, here is what I am thinking...

Based on my realtor's research somewhere around $33,000/acre in this area seems to be fair based on comps.  So, I'm wondering if I should offer them that price for 8 acres and nothing for the 2 with the house for his parents.  I would own the land but let them stay there.  So that totals $264,000.  BUT, I would subtract the amount to tear down the cabin AND fix the road up to it so that it is all set for potential buys who want to build.  I am thinking around $100,000 total for this.  That means I would offer them $164,000 for the whole 10 acres and let the parents live there until they die.  Then I would spend 100K on fixing it up and attempt to flip the 8 acres for profit leaving me the 2 acres free and clear even though they will be living there for who knows how long.  Complicated enough??  

He has the entire property listed right now at $429,00 but in the past year it has been all over the place from 399K-695K.  They may laugh my offer off which I am TOTALLY fine with.  Am I offering too much/little?  Any other ideas? Please feel free to speak in to any and all parts of this deal.  Thanks!

Josh