A superior court in Northampton County has upheld the ruling in the lengthy legal battle involving Lehigh Valley attorney John Karoly.
Karoly's brother Peter and his wife Lauren Angstadt were killed in a plane crash in 2007.
Karoly's sisters claimed that the wills had been forged, but in late August, a judge ruled the sisters failed to prove the documents were fake.
The sisters then appealed the ruling to a county judge, who upheld the ruling in April.
On Wednesday, a Superior Court affirmed the authenticity of the wills.
Karoly is currently serving a six-year jail sentence for tax evasion, mail fraud and money laundering.