Seller trying to back out of a deal 2 weeks after the contract

[Michael Bachmann]

I have a contract with a seller and we are set to close on July 14th.  We extended the contract time to allow her to find another place to live.  The seller is getting older and is no longer able to take care of the place and has someone that is living with her to help driver her around and fix things around the house.  First the seller thought she was going to get her money before she moved and we closed on the property, we (the title company and myself) then explained that we would give her the agreed $1,250 moving money whenever she needed it however the actual sale price would be gotten at closing.  Now all of the sudden the person that she is living with doesn't want to move.  They both are on the deed (she added him 11 years ago after her husband died so he would take care of her) and they both signed the contract.  I have told her I would be happy to help her find another place to move to however the gentleman that she is living with is trying to convince her otherwise.

What can I do to at least keep them from trying to sell to someone at a later point?  I don't care if it takes her 4 months to find another place to move to, I am happy to wait.  It has taken 3 years to get to this point with the seller and I don't want the person she is living with to literally kill her off to get the house which is sadly what I think is going on here.  

I have heard of a memorandum of contract but not sure how to use that as all we got when we met with the signed contact and we provided that to the title company several weeks ago with the $250 deposit check for escrow.  

I would appreciate any advice that my fellow Bigger Pockets people can provide.