Property seperation/mortgage combination

Location: Oklahoma USA

Background information: My bank financed mobile home is on a section of my dad's property that is not Mortgaged, but is connected to the portion of his land that his home is on that is Mortgaged. The properties have separate addresses, but only one deed. I am essentially a renter of his property that is not required pay rent. He is approaching retirement and has decided to move overseas in approximately 2 years. Before then, he needs to sell me both properties.

The issue: I cannot afford 2 separate mortgages, but if both properties and homes were financed together, I could afford it without issue.

Question: what would be my options for getting a mortgage that buys the entire property, pays off his mortgage, and my mobile home? Given that his home and property it's on would apraise for enough to do that.