< or = to 0.1ng/ml has no significance. There is a diurnal rhythm to PSA. And it can be affected by activity.
Some labs recommend a 7-9 hour fast. He is a long, long way from 3.0ng/ml. And there is no need to worry until >3.99ng/ml. Prostate Specific Antigen ( a misnomer) isn't specific to the prostate. Even salivary glands produce a little.
Still, don't stop worrying; it's such a lovely thing in a daughter. You must have a good dad.
Bless you both.