The doctors are saying in his 40s. My husband's grandfather also had prostate cancer.

I was diagnosed at age 48 (4 years ago). Had a large amount of aggressive cancer but was contained in prostate. I was being checked out for something unrelated when doctor asked about prostate cancer in family and told him my father had it (radiation treatment). They did biopsy. My only option was radical prostatectomy. Had I waited to get tested till 50 like many doctors will tell you, I would have never seen 50. Dealing with ED and incontinence but I'm alive. Bottom line is it's never too early to get checked out if there is history of it in family.

Not sure what age your husband is but get checked as soon as his doc says to. Let him know the family history.
My husband got checked each year since he was in his late 20's because of the family history.
They found the cancer when my hubby was 45! He did radiation for 8 weeks and so far no more cancer. It will be 5 years this year.
We are greatful that the docs found it early.
His Dad is 81 and has prostate cancer which they can't do much for now.
So have him checked when the docs say to.

FIL died and cancer was all through him. Get checked ASAP! Maybe the doctors can do more now. Technology is way different since my FIL was diagnosed more than 20 years ago.
Lets give Cancer the boot!!!!
ttfn

The test, which can be done at a GP surgery, measures the level of PSA prostate-specific antigen in your blood it is very essential when someone diagnosed with prostate cancer. If early prostate cancer is found, the treatment you receive will depend on your individual circumstances.

After age 40 he should get tested. Make sure he gets the DRE (fickle finger) test in addition to PSA labwork. I have cancer and had a normal PSA of 2.7. The DRE turned up the prostate problem.