Looks like unless I had 230k in my mattress and an attorney willing to notarize a deed this deal is dead. 

I often see people talk to people like they are the Spawn of Satan if they say they are making a "cash offer" and don't have the actual money in a bank account, liquidatable stock account, or stuffed in a mattress as they don't trust them there banks!

I have an extra mattress and box spring I’d be willing to donate (I really don’t need it).

Depending on the income potential and budgetary constraints, we can scale the 'standard' product list up or down (for example, buy a $300 mattress instead of a $2,000 mattress).

It will return about 3% more than putting it under your mattress and it will be relatively safe till the markets turn.

I've sold everything I own and stashed the cash under a mattress.

If all other units in your area that you will compete have, for example, two king sized beds with memory foam mattresses, then you probably have to get that too.

Well, if your family members have $80k cash under the mattress, then they will need explanation.  

It is very sad for a investor to read that someone has stuffed their money under a mattress where it is earning absolutely no income, It is not earning it's keep lying dead and buried in a property, rental or personal, it needs to be flogged.

The owner currently provides a single bed and mattress, plus so rudimentary furniture.