Help with how to propose owner financing on this deal

[Travis Williams]

I am looking at a deal on a small 2 bedroom home and 2 adjoining lots for 35k. Seller is motivated. It is his mothers home and she is very ill. I would like to structure an owner financed deal for this property that could benefit myself as well as the seller. The son who is caring for his mother wants to sell the property before his mother passes so he doesn't have to deal with other siblings that have been less than helpful apparently. I was informed that there is a heloc with a balance of around 28k. So the equity left is around 7k. When I first asked about owner finance he said he would be willing to finance the equity but wanted to pay off the heloc. Should I suggest paying their equity as a down payment then payments with a slightly higher rate than the heloc so they can make a slight profit on the spread. Could I do this as a contract for deed? Suggestions....?