My dad liver was slighly enflamed what is the meaning of that?

Inflammation: can be caused by alcohol, fat, viral hepatitis, multiple autoimmune causes. This is by blood tests I presume? i'd speak to the physician that ordered the tests for further clarification.

Which hepatitis?: "hepatitis" is a generic term that means your liver is inflamed. This can be caused by infection with viruses (like a, b, c, d, e, etc, cmv, ebv), parasites, bacteria. Non-infectious causes include: alcohol, toxin exposure, occupational risk, drugs (like tylenol (acetaminophen) overdose), familial liver diseases, ischemic damage, heart problems, infiltrative pathology, trauma, etc. More info please so we can help