I'm sure if your dad has had liver problems for awhile the doctors would have run a hepatitis panal on your dad. This is an inexpensive blood test checking for hepatitis A,B or C antibodies.
Best of luck
In order to find out if someone has hepatitis C a specific blood test has to be run.
It isn't automatically tested for.
He certainly could have gotten it from a tattoo as well as a number of other ways.
Many people have no idea how they got it.