If the property is eligible for a standard
mortgage, my suggestion would be to try to come to an agreement with Dad and your sibling about what "fair" looks like. Dad can then give you a "gift of equity" equal to whatever your fair share of the farm's value is. What that means is, you would buy the house from him for market price, but the amount you actually owed would be offset by the
gift of equity. It basically acts like a down payment for you.
As an example, using made up numbers: If the farm is worth $400,000 and you all agree that it
should be split 50/50 between you and your sibling, Dad would agree to
sell it to you for $400,000 with a $200,000
gift of equity. Your mortgage calculations will all be based on a $400,000 purchase price with $200,000 down (the equity gift) so your loan to value ratio is at 50% meaning that you get the best available rates, no mortgage insurance, and the overall risk is lowered making it easier to be approved. At closing, Dad will get a check for $200,000 (minus any taxes, fees, etc.) which he can give to sibling. Then the house bit is done, and when he passes you can take on the task of dividing the rest of the assets in whatever way makes sense.
I do mortgages for a living, and have helped clients with several similar situations over the years. Let me know if there are other questions I might be able to
answer.