I think you have the misconception of PSA test. It is not the only thing needed to determine no need to worry. What are his symptoms?

Most urologist will do a a DRE to feel the prostate for obivious feel of an abnormality. Getting a PSA test will only give you a number. It does not tell you if you have cancer, or BPH. Based on PSA test and DRE that can help but not completely determine need to have further test.

Individuals with high PSA is not a diagnosis of cancer. A low PSA does not mean you do not have cancer. I had a normal PSA and I was diagnosed with cancer.
I think important that we do not infer we are medical experts on MCC and you take that as medical guidance. We can give you our personal experiences and be an inspirations but should not be seen as giving you medical guidance.

The below was taken from WEB MD. It is the basic information on prostate cancer. You can go on web sites like WEBMD, Mayo, Cleveland Clinic, John Hopkins, etc. to get medical information on BPH and prostate cancer. Look at the basis and you will see getting a PSA test is not to be seen as a test that rules out cancer or rules it in. And that is from the medical community not me as you can read below.
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Screening: DRE and PSA
Your doctor may initially do a digital rectal exam (DRE) to feel for bumps or hard spots on the prostate. After a discussion with your doctor, a blood test can be used to measure prostate-specific antigen (PSA), a protein produced by prostate cells. An elevated level may indicate a higher chance that you have cancer, but you can have a high level and still be cancer-free. It is also possible to have a normal PSA and have prostate cancer.

PSA Test Results
A normal PSA level is considered to be under 4 nanograms per milliliter (ng/mL) of blood, while a PSA above 10 suggests a high risk of cancer. But there are many exceptions:

Men can have prostate cancer with a PSA less than 4.
A prostate that is inflamed (prostatitis) or enlarged (BPH) can boost PSA levels, yet further testing may show no evidence of cancer.
Some BPH drugs can lower PSA levels, despite the presence of prostate cancer, called a false negative.
If either a PSA or DRE test are abnormal, your doctor will likely order other tests.