Creative financing to keep the current mortgage in place

[David Hedges]

I have a family member who is asking me for help. 

I've run through the numbers on their house, and it all works if I can keep their current mortgage in place. I'm looking for some ideas on how I should structure this. 

I'd floated the idea of a lease option, with a 5-year term and possible 5-year extension if I'm not able to get acceptable financing at that point. That seemed acceptable, but I wasn't sure if there might be a better way of going about this or other alternatives. 

I'd be taking over their mortgage, paying tax, taking on maintenance, and any other expenses related to it over the term, with them getting paid out the agreed-upon amount within the option period of 5-10 years.