Degarelix is used in these cases because it starts starving the cancer immediately - you will probably see the PSA drop remarkably quickly.
The highest PSA at diagnosis we have seen on this forum was 13,000 and he lived reasonably well for 5 years despite a number of serious complications, some of which had nothing to do with prostate cancer. Our urologist says that the highest PSA he has ever seen in a patient was 160,000! It is hard to grasp this when you will see men on here worrying because their PSA has risen above 0.2 ... it all depends on what treatment they have had or are having.
Your husband is what is referred to as hormone naive; once his bloods are sorted, they may suggest adding other treatments to help the degarelix do its job for longer. As Dave has said, the shock does settle and you will eventually find your new normal.
You don’t say how old he is?