I want to give two answers here (as a layperson/non-expert):

1. Having the BRCA mutations isn't catastropic: as @jeffmarc has pointed out, oncologists have effective tools for managing PCa with those mutations now.

2. But still, that's great news for your husband. Not having the BRCA mutations means the cancer has less genomic instability, and is less likely to develop features of the (very rare) neuroendocrine variety of prostate cancer (NEPC), which requires more aggressive and urgent treatment. (The primary drivers for NEPC are low or absent TP53 and RB1 — your husband may or may not have been tested for those, because they can change over time.)

So yes, it's definitely time to celebrate! 🎉 Every bit of good news is cause for celebration in prostate-cancer land, and this is an important one.

But for others reading this who do have the BRCA mutations and/or NEPC, don't get discouraged: new research and treatments are a rising tide, and as the saying goes, a rising tide floats all boats (including yours). The outlook is improving for all of us.