Inquiry - input needed (discounted note)

[George P.]

Someone called off my letter that I sent 4 years ago.
Long story short, 3-4 yrs ago, three heirs inherited a house and later sold it to a son of the 3rd heir. First two heirs jointly financed 2/3 of the loan (one note), the 3rd "donated" her 1/3 of the equity to her son. The original plan was to wait a year and have a borrower re-fi with his mother (3rd heir) being a co-signer.
As it always happens, people change their minds. Now the 2 note holders are "tired" (I quote) and want out for 2/3 of the balance (44k).
Numbers:
- Appx balance 65k
- originally financed 68.6 @ 6% for 30 yrs, 27 years left
- FMV 75-85 (I am being very conservative), back when the house was sold the RE market was strong.
- PI Payment is $411, current.
- The property is within 45 minute drive from me.

Noteholder assures the borrower doesn't miss a payment, although his credit is bad (alas the owner financing). Prop taxes and insurance (TI) are paid by the borrower, not through the escrow. I checked the property taxes, they are current.

I have never investigated notes, so I am looking for suggestions in evaluating.
Thanks in advance for any input.