Figuring historical basis on inherited property

Home originally owned by solely by parent for many decades.


Son takes 1% interest then full interest as follows:

March 15, 2010
1% interest/99% remainder (recorded on deed)
April 17, 2010
Parent died
Son now has 100% interest

 

September, 2022
Son now selling for $60,000.
How do we determine original basis?
Is it value at parents death?
Can an historical appraisal be used to provide that value?

Thank you in advance.