Good idea to purchase parents' mobile home?

[Troy P.]

To make a long story short, my mother passed away last year and my step father is living in their mobile home with a relatively high interest rate and no banks willing to refinance.  We recently started tossing around the idea of purchasing it myself and him paying me "rent" which would essentially come out to break even cash flow.  I know rent will come on time every month and I know eventually it will be easier if this is done now rather than dealing with a mortgage I can't control.  He has a plethora of health issue so I'm thinking about this long-term and whether this will be a good buy and hold investment.  It sits on .25 acres which is also owned by him.

My initial thought was to do a Sub-2 on the property then eventually refinance into my own name shortly after.  That would prevent a 20% down payment needed to complete the deal, is that correct?  I want to help him get out of the high interest loan while also starting to build my portfolio of rental properties.  Are there better ways to approach this??