one is disability, Ssdi, and that ends or converts to social security, Ssi, when you reach full retirement age of 67.. don’t know about collecting outside of the country but will find out soon enough
Does she own the land free and clear? If so I think you have her get a loan against it then use that money to pay for new house and you happily make loan payments.. should the wheels fall off you simply go away and she does what she has to do.. asking them to take some risk and responsibility but no financial obligation is fair.. she trusts you and you trust her, easy peasy-maybe!!